api-documenter examples

algorithm.arrayext.fill.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [fill](./algorithm.arrayext.fill.md)

## ArrayExt.fill() function

Fill an array with a static value.

<b>Signature:</b>

```typescript
function fill<T>(array: MutableArrayLike<T>, value: T, start?: number, stop?: number): void;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>MutableArrayLike&lt;T&gt;</code> | The mutable array-like object to fill. |
|  value | <code>T</code> | The static value to use to fill the array. |
|  start | <code>number</code> | The index of the first element in the range to be filled, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be filled, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array.<!-- -->\#\#\#\# Notes If <code>stop &lt; start</code> the fill will wrap at the end of the array.<!-- -->\#\#\#\# Complexity Linear.<!-- -->\#\#\#\# Undefined Behavior A <code>start</code> or <code>stop</code> which is non-integral.<!-- -->\#\#\#\# Example
```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = ['one', 'two', 'three', 'four'];
ArrayExt.fill(data, 'r');        // ['r', 'r', 'r', 'r']
ArrayExt.fill(data, 'g', 1);     // ['r', 'g', 'g', 'g']
ArrayExt.fill(data, 'b', 2, 3);  // ['r', 'g', 'b', 'b']
ArrayExt.fill(data, 'z', 3, 1);  // ['z', 'z', 'b', 'z']

```
 |

<b>Returns:</b>

`void`

algorithm.arrayext.findfirstindex.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [findFirstIndex](./algorithm.arrayext.findfirstindex.md)

## ArrayExt.findFirstIndex() function

Find the index of the first value which matches a predicate.

<b>Signature:</b>

```typescript
function findFirstIndex<T>(array: ArrayLike<T>, fn: (value: T, index: number) => boolean, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>ArrayLike&lt;T&gt;</code> | The array-like object to search. |
|  fn | <code>(value: T, index: number) =&gt; boolean</code> | The predicate function to apply to the values. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The index of the first matching value, or `-1` if no matching value is found.

\#\#\#\# Notes If `stop < start` the search will wrap at the end of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Undefined Behavior A `start` or `stop` which is non-integral.

Modifying the length of the array while searching.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function isEven(value: number): boolean {
  return value % 2 === 0;
}

let data = [1, 2, 3, 4, 3, 2, 1];
ArrayExt.findFirstIndex(data, isEven);       // 1
ArrayExt.findFirstIndex(data, isEven, 4);    // 5
ArrayExt.findFirstIndex(data, isEven, 6);    // -1
ArrayExt.findFirstIndex(data, isEven, 6, 5); // 1

```

algorithm.arrayext.findfirstvalue.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [findFirstValue](./algorithm.arrayext.findfirstvalue.md)

## ArrayExt.findFirstValue() function

Find the first value which matches a predicate.

<b>Signature:</b>

```typescript
function findFirstValue<T>(array: ArrayLike<T>, fn: (value: T, index: number) => boolean, start?: number, stop?: number): T | undefined;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>ArrayLike&lt;T&gt;</code> | The array-like object to search. |
|  fn | <code>(value: T, index: number) =&gt; boolean</code> | The predicate function to apply to the values. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`T | undefined`

The first matching value, or `undefined` if no matching value is found.

\#\#\#\# Notes If `stop < start` the search will wrap at the end of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Undefined Behavior A `start` or `stop` which is non-integral.

Modifying the length of the array while searching.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function isEven(value: number): boolean {
  return value % 2 === 0;
}

let data = [1, 2, 3, 4, 3, 2, 1];
ArrayExt.findFirstValue(data, isEven);       // 2
ArrayExt.findFirstValue(data, isEven, 2);    // 4
ArrayExt.findFirstValue(data, isEven, 6);    // undefined
ArrayExt.findFirstValue(data, isEven, 6, 5); // 2

```

algorithm.arrayext.findlastindex.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [findLastIndex](./algorithm.arrayext.findlastindex.md)

## ArrayExt.findLastIndex() function

Find the index of the last value which matches a predicate.

<b>Signature:</b>

```typescript
function findLastIndex<T>(array: ArrayLike<T>, fn: (value: T, index: number) => boolean, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>ArrayLike&lt;T&gt;</code> |  |
|  fn | <code>(value: T, index: number) =&gt; boolean</code> | The predicate function to apply to the values. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The index of the last matching value, or `-1` if no matching value is found.

\#\#\#\# Notes If `start < stop` the search will wrap at the front of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Undefined Behavior A `start` or `stop` which is non-integral.

Modifying the length of the array while searching.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function isEven(value: number): boolean {
  return value % 2 === 0;
}

let data = [1, 2, 3, 4, 3, 2, 1];
ArrayExt.findLastIndex(data, isEven);        // 5
ArrayExt.findLastIndex(data, isEven, 4);     // 3
ArrayExt.findLastIndex(data, isEven, 0);     // -1
ArrayExt.findLastIndex(data, isEven, 0, 1);  // 5

```

algorithm.arrayext.findlastvalue.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [findLastValue](./algorithm.arrayext.findlastvalue.md)

## ArrayExt.findLastValue() function

Find the last value which matches a predicate.

<b>Signature:</b>

```typescript
function findLastValue<T>(array: ArrayLike<T>, fn: (value: T, index: number) => boolean, start?: number, stop?: number): T | undefined;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>ArrayLike&lt;T&gt;</code> |  |
|  fn | <code>(value: T, index: number) =&gt; boolean</code> | The predicate function to apply to the values. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`T | undefined`

The last matching value, or `undefined` if no matching value is found.

\#\#\#\# Notes If `start < stop` the search will wrap at the front of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Undefined Behavior A `start` or `stop` which is non-integral.

Modifying the length of the array while searching.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function isEven(value: number): boolean {
  return value % 2 === 0;
}

let data = [1, 2, 3, 4, 3, 2, 1];
ArrayExt.findLastValue(data, isEven);        // 2
ArrayExt.findLastValue(data, isEven, 4);     // 4
ArrayExt.findLastValue(data, isEven, 0);     // undefined
ArrayExt.findLastValue(data, isEven, 0, 1);  // 2

```

algorithm.arrayext.firstindexof.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [firstIndexOf](./algorithm.arrayext.firstindexof.md)

## ArrayExt.firstIndexOf() function

Find the index of the first occurrence of a value in an array.

<b>Signature:</b>

```typescript
function firstIndexOf<T>(array: ArrayLike<T>, value: T, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>ArrayLike&lt;T&gt;</code> | The array-like object to search. |
|  value | <code>T</code> | The value to locate in the array. Values are compared using strict <code>===</code> equality. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The index of the first occurrence of the value, or `-1` if the value is not found.

\#\#\#\# Notes If `stop < start` the search will wrap at the end of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Undefined Behavior A `start` or `stop` which is non-integral.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = ['one', 'two', 'three', 'four', 'one'];
ArrayExt.firstIndexOf(data, 'red');        // -1
ArrayExt.firstIndexOf(data, 'one');        // 0
ArrayExt.firstIndexOf(data, 'one', 1);     // 4
ArrayExt.firstIndexOf(data, 'two', 2);     // -1
ArrayExt.firstIndexOf(data, 'two', 2, 1);  // 1

```

algorithm.arrayext.insert.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [insert](./algorithm.arrayext.insert.md)

## ArrayExt.insert() function

Insert a value into an array at a specific index.

<b>Signature:</b>

```typescript
function insert<T>(array: Array<T>, index: number, value: T): void;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  index | <code>number</code> | The index at which to insert the value. Negative values are taken as an offset from the end of the array. |
|  value | <code>T</code> | The value to set at the specified index.<!-- -->\#\#\#\# Complexity Linear.<!-- -->\#\#\#\# Undefined Behavior An <code>index</code> which is non-integral.<!-- -->\#\#\#\# Example
```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = [0, 1, 2];
ArrayExt.insert(data, 0, -1);  // [-1, 0, 1, 2]
ArrayExt.insert(data, 2, 12);  // [-1, 0, 12, 1, 2]
ArrayExt.insert(data, -1, 7);  // [-1, 0, 12, 1, 7, 2]
ArrayExt.insert(data, 6, 19);  // [-1, 0, 12, 1, 7, 2, 19]

```
 |

<b>Returns:</b>

`void`

algorithm.arrayext.lastindexof.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [lastIndexOf](./algorithm.arrayext.lastindexof.md)

## ArrayExt.lastIndexOf() function

Find the index of the last occurrence of a value in an array.

<b>Signature:</b>

```typescript
function lastIndexOf<T>(array: ArrayLike<T>, value: T, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>ArrayLike&lt;T&gt;</code> | The array-like object to search. |
|  value | <code>T</code> | The value to locate in the array. Values are compared using strict <code>===</code> equality. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The index of the last occurrence of the value, or `-1` if the value is not found.

\#\#\#\# Notes If `start < stop` the search will wrap at the front of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Undefined Behavior A `start` or `stop` which is non-integral.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = ['one', 'two', 'three', 'four', 'one'];
ArrayExt.lastIndexOf(data, 'red');        // -1
ArrayExt.lastIndexOf(data, 'one');        // 4
ArrayExt.lastIndexOf(data, 'one', 1);     // 0
ArrayExt.lastIndexOf(data, 'two', 0);     // -1
ArrayExt.lastIndexOf(data, 'two', 0, 1);  // 1

```

algorithm.arrayext.lowerbound.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [lowerBound](./algorithm.arrayext.lowerbound.md)

## ArrayExt.lowerBound() function

Find the index of the first element which compares `>=` to a value.

<b>Signature:</b>

```typescript
function lowerBound<T, U>(array: ArrayLike<T>, value: U, fn: (element: T, value: U) => number, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>ArrayLike&lt;T&gt;</code> | The sorted array-like object to search. |
|  value | <code>U</code> | The value to locate in the array. |
|  fn | <code>(element: T, value: U) =&gt; number</code> | The 3-way comparison function to apply to the values. It should return <code>&lt; 0</code> if an element is less than a value, <code>0</code> if an element is equal to a value, or <code>&gt; 0</code> if an element is greater than a value. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The index of the first element which compares `>=` to the value, or `length` if there is no such element. If the computed index for `stop` is less than `start`<!-- -->, then the computed index for `start` is returned.

\#\#\#\# Notes The array must already be sorted in ascending order according to the comparison function.

\#\#\#\# Complexity Logarithmic.

\#\#\#\# Undefined Behavior Searching a range which is not sorted in ascending order.

A `start` or `stop` which is non-integral.

Modifying the length of the array while searching.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function numberCmp(a: number, b: number): number {
  return a - b;
}

let data = [0, 3, 4, 7, 7, 9];
ArrayExt.lowerBound(data, 0, numberCmp);   // 0
ArrayExt.lowerBound(data, 6, numberCmp);   // 3
ArrayExt.lowerBound(data, 7, numberCmp);   // 3
ArrayExt.lowerBound(data, -1, numberCmp);  // 0
ArrayExt.lowerBound(data, 10, numberCmp);  // 6

```

algorithm.arrayext.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md)

## ArrayExt namespace

The namespace for array-specific algorithms.

<b>Signature:</b>

```typescript
export declare namespace ArrayExt 
```

## Functions

|  Function | Description |
|  --- | --- |
|  [fill(array, value, start, stop)](./algorithm.arrayext.fill.md) | Fill an array with a static value. |
|  [findFirstIndex(array, fn, start, stop)](./algorithm.arrayext.findfirstindex.md) | Find the index of the first value which matches a predicate. |
|  [findFirstValue(array, fn, start, stop)](./algorithm.arrayext.findfirstvalue.md) | Find the first value which matches a predicate. |
|  [findLastIndex(array, fn, start, stop)](./algorithm.arrayext.findlastindex.md) | Find the index of the last value which matches a predicate. |
|  [findLastValue(array, fn, start, stop)](./algorithm.arrayext.findlastvalue.md) | Find the last value which matches a predicate. |
|  [firstIndexOf(array, value, start, stop)](./algorithm.arrayext.firstindexof.md) | Find the index of the first occurrence of a value in an array. |
|  [insert(array, index, value)](./algorithm.arrayext.insert.md) | Insert a value into an array at a specific index. |
|  [lastIndexOf(array, value, start, stop)](./algorithm.arrayext.lastindexof.md) | Find the index of the last occurrence of a value in an array. |
|  [lowerBound(array, value, fn, start, stop)](./algorithm.arrayext.lowerbound.md) | Find the index of the first element which compares <code>&gt;=</code> to a value. |
|  [move(array, fromIndex, toIndex)](./algorithm.arrayext.move.md) | Move an element in an array from one index to another. |
|  [removeAllOf(array, value, start, stop)](./algorithm.arrayext.removeallof.md) | Remove all occurrences of a value from an array. |
|  [removeAllWhere(array, fn, start, stop)](./algorithm.arrayext.removeallwhere.md) | Remove all occurrences of values which match a predicate. |
|  [removeAt(array, index)](./algorithm.arrayext.removeat.md) | Remove and return a value at a specific index in an array. |
|  [removeFirstOf(array, value, start, stop)](./algorithm.arrayext.removefirstof.md) | Remove the first occurrence of a value from an array. |
|  [removeFirstWhere(array, fn, start, stop)](./algorithm.arrayext.removefirstwhere.md) | Remove the first occurrence of a value which matches a predicate. |
|  [removeLastOf(array, value, start, stop)](./algorithm.arrayext.removelastof.md) | Remove the last occurrence of a value from an array. |
|  [removeLastWhere(array, fn, start, stop)](./algorithm.arrayext.removelastwhere.md) | Remove the last occurrence of a value which matches a predicate. |
|  [reverse(array, start, stop)](./algorithm.arrayext.reverse.md) | Reverse an array in-place. |
|  [rotate(array, delta, start, stop)](./algorithm.arrayext.rotate.md) | Rotate the elements of an array in-place. |
|  [shallowEqual(a, b, fn)](./algorithm.arrayext.shallowequal.md) | Test whether two arrays are shallowly equal. |
|  [slice(array, options)](./algorithm.arrayext.slice.md) | Create a slice of an array subject to an optional step. |
|  [upperBound(array, value, fn, start, stop)](./algorithm.arrayext.upperbound.md) | Find the index of the first element which compares <code>&gt;</code> than a value. |

## Namespaces

|  Namespace | Description |
|  --- | --- |
|  [slice](./algorithm.arrayext.slice.md) | The namespace for the <code>slice</code> function statics. |

## Type Aliases

|  Type Alias | Description |
|  --- | --- |
|  [MutableArrayLike](./algorithm.arrayext.mutablearraylike.md) | An array-like object which supports item assignment. |

algorithm.arrayext.move.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [move](./algorithm.arrayext.move.md)

## ArrayExt.move() function

Move an element in an array from one index to another.

<b>Signature:</b>

```typescript
function move<T>(array: MutableArrayLike<T>, fromIndex: number, toIndex: number): void;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>MutableArrayLike&lt;T&gt;</code> | The mutable array-like object of interest. |
|  fromIndex | <code>number</code> | The index of the element to move. Negative values are taken as an offset from the end of the array. |
|  toIndex | <code>number</code> | The target index of the element. Negative values are taken as an offset from the end of the array.<!-- -->\#\#\#\# Complexity Linear.<!-- -->\#\#\#\# Undefined Behavior A <code>fromIndex</code> or <code>toIndex</code> which is non-integral.<!-- -->\#\#\#\# Example
```typescript
import { ArrayExt } from from '@lumino/algorithm';

let data = [0, 1, 2, 3, 4];
ArrayExt.move(data, 1, 2);  // [0, 2, 1, 3, 4]
ArrayExt.move(data, 4, 2);  // [0, 2, 4, 1, 3]

```
 |

<b>Returns:</b>

`void`

algorithm.arrayext.mutablearraylike.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [MutableArrayLike](./algorithm.arrayext.mutablearraylike.md)

## ArrayExt.MutableArrayLike type

An array-like object which supports item assignment.

<b>Signature:</b>

```typescript
type MutableArrayLike<T> = {
        readonly length: number;
        [index: number]: T;
    };
```

algorithm.arrayext.removeallof.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [removeAllOf](./algorithm.arrayext.removeallof.md)

## ArrayExt.removeAllOf() function

Remove all occurrences of a value from an array.

<b>Signature:</b>

```typescript
function removeAllOf<T>(array: Array<T>, value: T, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  value | <code>T</code> | The value to remove from the array. Values are compared using strict <code>===</code> equality. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The number of elements removed from the array.

\#\#\#\# Notes If `stop < start` the search will conceptually wrap at the end of the array, however the array will be traversed front-to-back.

\#\#\#\# Complexity Linear.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = [14, 12, 23, 39, 14, 12, 19, 14];
ArrayExt.removeAllOf(data, 12);        // 2
ArrayExt.removeAllOf(data, 17);        // 0
ArrayExt.removeAllOf(data, 14, 1, 4);  // 1

```

algorithm.arrayext.removeallwhere.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [removeAllWhere](./algorithm.arrayext.removeallwhere.md)

## ArrayExt.removeAllWhere() function

Remove all occurrences of values which match a predicate.

<b>Signature:</b>

```typescript
function removeAllWhere<T>(array: Array<T>, fn: (value: T, index: number) => boolean, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  fn | <code>(value: T, index: number) =&gt; boolean</code> | The predicate function to apply to the values. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The number of elements removed from the array.

\#\#\#\# Notes If `stop < start` the search will conceptually wrap at the end of the array, however the array will be traversed front-to-back.

\#\#\#\# Complexity Linear.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function isEven(value: number): boolean {
  return value % 2 === 0;
}

function isNegative(value: number): boolean {
  return value < 0;
}

let data = [0, 12, -13, -9, 23, 39, 14, -15, 12, 75];
ArrayExt.removeAllWhere(data, isEven);            // 4
ArrayExt.removeAllWhere(data, isNegative, 0, 3);  // 2

```

algorithm.arrayext.removeat.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [removeAt](./algorithm.arrayext.removeat.md)

## ArrayExt.removeAt() function

Remove and return a value at a specific index in an array.

<b>Signature:</b>

```typescript
function removeAt<T>(array: Array<T>, index: number): T | undefined;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  index | <code>number</code> | The index of the value to remove. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`T | undefined`

The value at the specified index, or `undefined` if the index is out of range.

\#\#\#\# Complexity Linear.

\#\#\#\# Undefined Behavior An `index` which is non-integral.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = [0, 12, 23, 39, 14, 12, 75];
ArrayExt.removeAt(data, 2);   // 23
ArrayExt.removeAt(data, -2);  // 12
ArrayExt.removeAt(data, 10);  // undefined;

```

algorithm.arrayext.removefirstof.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [removeFirstOf](./algorithm.arrayext.removefirstof.md)

## ArrayExt.removeFirstOf() function

Remove the first occurrence of a value from an array.

<b>Signature:</b>

```typescript
function removeFirstOf<T>(array: Array<T>, value: T, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  value | <code>T</code> | The value to remove from the array. Values are compared using strict <code>===</code> equality. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The index of the removed value, or `-1` if the value is not contained in the array.

\#\#\#\# Notes If `stop < start` the search will wrap at the end of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = [0, 12, 23, 39, 14, 12, 75];
ArrayExt.removeFirstOf(data, 12);        // 1
ArrayExt.removeFirstOf(data, 17);        // -1
ArrayExt.removeFirstOf(data, 39, 3);     // -1
ArrayExt.removeFirstOf(data, 39, 3, 2);  // 2

```

algorithm.arrayext.removefirstwhere.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [removeFirstWhere](./algorithm.arrayext.removefirstwhere.md)

## ArrayExt.removeFirstWhere() function

Remove the first occurrence of a value which matches a predicate.

<b>Signature:</b>

```typescript
function removeFirstWhere<T>(array: Array<T>, fn: (value: T, index: number) => boolean, start?: number, stop?: number): {
        index: number;
        value: T | undefined;
    };
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  fn | <code>(value: T, index: number) =&gt; boolean</code> | The predicate function to apply to the values. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`{
        index: number;
        value: T | undefined;
    }`

The removed `{ index, value }`<!-- -->, which will be `-1` and `undefined` if the value is not contained in the array.

\#\#\#\# Notes If `stop < start` the search will wrap at the end of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function isEven(value: number): boolean {
  return value % 2 === 0;
}

let data = [0, 12, 23, 39, 14, 12, 75];
ArrayExt.removeFirstWhere(data, isEven);     // { index: 0, value: 0 }
ArrayExt.removeFirstWhere(data, isEven, 2);  // { index: 3, value: 14 }
ArrayExt.removeFirstWhere(data, isEven, 4);  // { index: -1, value: undefined }

```

algorithm.arrayext.removelastof.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [removeLastOf](./algorithm.arrayext.removelastof.md)

## ArrayExt.removeLastOf() function

Remove the last occurrence of a value from an array.

<b>Signature:</b>

```typescript
function removeLastOf<T>(array: Array<T>, value: T, start?: number, stop?: number): number;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  value | <code>T</code> | The value to remove from the array. Values are compared using strict <code>===</code> equality. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`number`

The index of the removed value, or `-1` if the value is not contained in the array.

\#\#\#\# Notes If `start < stop` the search will wrap at the end of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = [0, 12, 23, 39, 14, 12, 75];
ArrayExt.removeLastOf(data, 12);        // 5
ArrayExt.removeLastOf(data, 17);        // -1
ArrayExt.removeLastOf(data, 39, 2);     // -1
ArrayExt.removeLastOf(data, 39, 2, 3);  // 3

```

algorithm.arrayext.removelastwhere.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [removeLastWhere](./algorithm.arrayext.removelastwhere.md)

## ArrayExt.removeLastWhere() function

Remove the last occurrence of a value which matches a predicate.

<b>Signature:</b>

```typescript
function removeLastWhere<T>(array: Array<T>, fn: (value: T, index: number) => boolean, start?: number, stop?: number): {
        index: number;
        value: T | undefined;
    };
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>Array&lt;T&gt;</code> | The array of interest. |
|  fn | <code>(value: T, index: number) =&gt; boolean</code> | The predicate function to apply to the values. |
|  start | <code>number</code> | The index of the first element in the range to be searched, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be searched, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |

<b>Returns:</b>

`{
        index: number;
        value: T | undefined;
    }`

The removed `{ index, value }`<!-- -->, which will be `-1` and `undefined` if the value is not contained in the array.

\#\#\#\# Notes If `start < stop` the search will wrap at the end of the array.

\#\#\#\# Complexity Linear.

\#\#\#\# Example

```typescript
import { ArrayExt } from '@lumino/algorithm';

function isEven(value: number): boolean {
  return value % 2 === 0;
}

let data = [0, 12, 23, 39, 14, 12, 75];
ArrayExt.removeLastWhere(data, isEven);        // { index: 5, value: 12 }
ArrayExt.removeLastWhere(data, isEven, 2);     // { index: 1, value: 12 }
ArrayExt.removeLastWhere(data, isEven, 2, 1);  // { index: -1, value: undefined }

```

algorithm.arrayext.reverse.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [reverse](./algorithm.arrayext.reverse.md)

## ArrayExt.reverse() function

Reverse an array in-place.

<b>Signature:</b>

```typescript
function reverse<T>(array: MutableArrayLike<T>, start?: number, stop?: number): void;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  array | <code>MutableArrayLike&lt;T&gt;</code> | The mutable array-like object of interest. |
|  start | <code>number</code> | The index of the first element in the range to be reversed, inclusive. The default value is <code>0</code>. Negative values are taken as an offset from the end of the array. |
|  stop | <code>number</code> | The index of the last element in the range to be reversed, inclusive. The default value is <code>-1</code>. Negative values are taken as an offset from the end of the array.<!-- -->\#\#\#\# Complexity Linear.<!-- -->\#\#\#\# Undefined Behavior A <code>start</code> or <code>stop</code> index which is non-integral.<!-- -->\#\#\#\# Example
```typescript
import { ArrayExt } from '@lumino/algorithm';

let data = [0, 1, 2, 3, 4];
ArrayExt.reverse(data, 1, 3);  // [0, 3, 2, 1, 4]
ArrayExt.reverse(data, 3);     // [0, 3, 2, 4, 1]
ArrayExt.reverse(data);        // [1, 4, 2, 3, 0]

```
 |

<b>Returns:</b>

`void`

algorithm.arrayext.rotate.md

algorithm.arrayext.shallowequal.md

algorithm.arrayext.slice.ioptions.md

algorithm.arrayext.slice.ioptions.start.md

<!-- Do not edit this file. It is automatically generated by API Documenter. -->

[Home](./index.md) &gt; [@lumino/algorithm](./algorithm.md) &gt; [ArrayExt](./algorithm.arrayext.md) &gt; [slice](./algorithm.arrayext.slice.md) &gt; [IOptions](./algorithm.arrayext.slice.ioptions.md) &gt; [start](./algorithm.arrayext.slice.ioptions.start.md)

## ArrayExt.slice.IOptions.start property

The starting index of the slice, inclusive.

Negative values are taken as an offset from the end of the array.

The default is `0` if `step > 0` else `n - 1`<!-- -->.

<b>Signature:</b>

```typescript
start?: number;
```

algorithm.arrayext.slice.ioptions.step.md

algorithm.arrayext.slice.ioptions.stop.md

algorithm.arrayext.slice.md

algorithm.arrayext.upperbound.md

algorithm.arrayiterator._constructor_.md

algorithm.arrayiterator.clone.md

algorithm.arrayiterator.iter.md

algorithm.arrayiterator.md

algorithm.arrayiterator.next.md

algorithm.chain.md

algorithm.chainiterator._constructor_.md

algorithm.chainiterator.clone.md

algorithm.chainiterator.iter.md

algorithm.chainiterator.md

algorithm.chainiterator.next.md

algorithm.each.md

algorithm.empty.md

algorithm.emptyiterator._constructor_.md

algorithm.emptyiterator.clone.md

algorithm.emptyiterator.iter.md

algorithm.emptyiterator.md

algorithm.emptyiterator.next.md

algorithm.enumerate.md

algorithm.enumerateiterator._constructor_.md

algorithm.enumerateiterator.clone.md

algorithm.enumerateiterator.iter.md

algorithm.enumerateiterator.md

algorithm.enumerateiterator.next.md

algorithm.every.md

algorithm.filter.md

algorithm.filteriterator._constructor_.md

algorithm.filteriterator.clone.md

algorithm.filteriterator.iter.md

algorithm.filteriterator.md

algorithm.filteriterator.next.md

algorithm.find.md

algorithm.findindex.md

algorithm.fniterator._constructor_.md

algorithm.fniterator.clone.md

algorithm.fniterator.iter.md

algorithm.fniterator.md

algorithm.fniterator.next.md

algorithm.iiterable.iter.md

algorithm.iiterable.md

algorithm.iiterator.clone.md

algorithm.iiterator.md

algorithm.iiterator.next.md

algorithm.iretroable.md

algorithm.iretroable.retro.md

algorithm.itemiterator._constructor_.md

algorithm.itemiterator.clone.md

algorithm.itemiterator.iter.md

algorithm.itemiterator.md

algorithm.itemiterator.next.md

algorithm.iter.md

algorithm.iterableorarraylike.md

algorithm.iterfn.md

algorithm.iteritems.md

algorithm.iterkeys.md

algorithm.itervalues.md

algorithm.keyiterator._constructor_.md

algorithm.keyiterator.clone.md

algorithm.keyiterator.iter.md

algorithm.keyiterator.md

algorithm.keyiterator.next.md

algorithm.map.md

algorithm.mapiterator._constructor_.md

algorithm.mapiterator.clone.md

algorithm.mapiterator.iter.md

algorithm.mapiterator.md

algorithm.mapiterator.next.md

algorithm.max.md

algorithm.md

algorithm.min.md

algorithm.minmax.md

algorithm.once.md

algorithm.range.md

algorithm.rangeiterator._constructor_.md

algorithm.rangeiterator.clone.md

algorithm.rangeiterator.iter.md

algorithm.rangeiterator.md

algorithm.rangeiterator.next.md

algorithm.reduce.md

algorithm.reduce_1.md

algorithm.repeat.md

algorithm.repeatiterator._constructor_.md

algorithm.repeatiterator.clone.md

algorithm.repeatiterator.iter.md

algorithm.repeatiterator.md

algorithm.repeatiterator.next.md

algorithm.retro.md

algorithm.retroableorarraylike.md

algorithm.retroarrayiterator._constructor_.md

algorithm.retroarrayiterator.clone.md

algorithm.retroarrayiterator.iter.md

algorithm.retroarrayiterator.md

algorithm.retroarrayiterator.next.md

algorithm.some.md

algorithm.stride.md

algorithm.strideiterator._constructor_.md

algorithm.strideiterator.clone.md

algorithm.strideiterator.iter.md

algorithm.strideiterator.md

algorithm.strideiterator.next.md

algorithm.stringext.cmp.md

algorithm.stringext.findindices.md

algorithm.stringext.highlight.md

algorithm.stringext.imatchresult.indices.md

algorithm.stringext.imatchresult.md

algorithm.stringext.imatchresult.score.md

algorithm.stringext.matchsumofdeltas.md

algorithm.stringext.matchsumofsquares.md

algorithm.stringext.md

algorithm.take.md

algorithm.takeiterator._constructor_.md

algorithm.takeiterator.clone.md

algorithm.takeiterator.iter.md

algorithm.takeiterator.md

algorithm.takeiterator.next.md

algorithm.toarray.md

algorithm.toobject.md

algorithm.topologicsort.md

algorithm.valueiterator._constructor_.md

algorithm.valueiterator.clone.md

algorithm.valueiterator.iter.md

algorithm.valueiterator.md

algorithm.valueiterator.next.md

algorithm.zip.md

algorithm.zipiterator._constructor_.md

algorithm.zipiterator.clone.md

algorithm.zipiterator.iter.md

algorithm.zipiterator.md

algorithm.zipiterator.next.md

application.application._constructor_.md

application.application.activateplugin.md

application.application.addeventlisteners.md

application.application.attachshell.md

application.application.commands.md

application.application.contextmenu.md

application.application.evtcontextmenu.md

application.application.evtkeydown.md

application.application.evtresize.md

application.application.handleevent.md

application.application.hasplugin.md

application.application.ioptions.contextmenurenderer.md

application.application.ioptions.md

application.application.ioptions.shell.md

application.application.istartoptions.hostid.md

application.application.istartoptions.ignoreplugins.md

application.application.istartoptions.md

application.application.istartoptions.startplugins.md

application.application.listplugins.md

application.application.md

application.application.registerplugin.md

application.application.registerplugins.md

application.application.resolveoptionalservice.md

application.application.resolverequiredservice.md

application.application.shell.md

application.application.start.md

application.application.started.md

application.iplugin.activate.md

application.iplugin.autostart.md

application.iplugin.id.md

application.iplugin.md

application.iplugin.optional.md

application.iplugin.provides.md

application.iplugin.requires.md

application.md

collections.bplustree._constructor_.md

collections.bplustree.assign.md

collections.bplustree.at.md

collections.bplustree.clear.md

collections.bplustree.cmp.md

collections.bplustree.delete.md

collections.bplustree.first.md

collections.bplustree.from.md

collections.bplustree.get.md

collections.bplustree.has.md

collections.bplustree.indexof.md

collections.bplustree.insert.md

collections.bplustree.isempty.md

collections.bplustree.iter.md

collections.bplustree.last.md

collections.bplustree.md

collections.bplustree.remove.md

collections.bplustree.retro.md

collections.bplustree.retroslice.md

collections.bplustree.size.md

collections.bplustree.slice.md

collections.bplustree.update.md

collections.linkedlist._constructor_.md

collections.linkedlist.addfirst.md

collections.linkedlist.addlast.md

collections.linkedlist.assign.md

collections.linkedlist.clear.md

collections.linkedlist.first.md

collections.linkedlist.firstnode.md

collections.linkedlist.forwardnodeiterator._constructor_.md

collections.linkedlist.forwardnodeiterator.clone.md

collections.linkedlist.forwardnodeiterator.iter.md

collections.linkedlist.forwardnodeiterator.md

collections.linkedlist.forwardnodeiterator.next.md

collections.linkedlist.forwardvalueiterator._constructor_.md

collections.linkedlist.forwardvalueiterator.clone.md

collections.linkedlist.forwardvalueiterator.iter.md

collections.linkedlist.forwardvalueiterator.md

collections.linkedlist.forwardvalueiterator.next.md

collections.linkedlist.from.md

collections.linkedlist.inode.list.md

collections.linkedlist.inode.md

collections.linkedlist.inode.next.md

collections.linkedlist.inode.prev.md

collections.linkedlist.inode.value.md

collections.linkedlist.insertafter.md

collections.linkedlist.insertbefore.md

collections.linkedlist.isempty.md

collections.linkedlist.iter.md

collections.linkedlist.last.md

collections.linkedlist.lastnode.md

collections.linkedlist.length.md

collections.linkedlist.md

collections.linkedlist.nodes.md

collections.linkedlist.pop.md

collections.linkedlist.push.md

collections.linkedlist.removefirst.md

collections.linkedlist.removelast.md

collections.linkedlist.removenode.md

collections.linkedlist.retro.md

collections.linkedlist.retronodeiterator._constructor_.md

collections.linkedlist.retronodeiterator.clone.md

collections.linkedlist.retronodeiterator.iter.md

collections.linkedlist.retronodeiterator.md

collections.linkedlist.retronodeiterator.next.md

collections.linkedlist.retronodes.md

collections.linkedlist.retrovalueiterator._constructor_.md

collections.linkedlist.retrovalueiterator.clone.md

collections.linkedlist.retrovalueiterator.iter.md

collections.linkedlist.retrovalueiterator.md

collections.linkedlist.retrovalueiterator.next.md

collections.linkedlist.shift.md

collections.linkedlist.size.md

collections.linkedlist.unshift.md

collections.md

commands.commandregistry._constructor_.md

commands.commandregistry.addcommand.md

commands.commandregistry.addkeybinding.md

commands.commandregistry.caption.md

commands.commandregistry.classname.md

commands.commandregistry.commandchanged.md

commands.commandregistry.commandexecuted.md

commands.commandregistry.commandfunc.md

commands.commandregistry.dataset.md

commands.commandregistry.execute.md

commands.commandregistry.formatkeystroke.md

commands.commandregistry.hascommand.md

commands.commandregistry.icommandchangedargs.id.md

commands.commandregistry.icommandchangedargs.md

commands.commandregistry.icommandchangedargs.type.md

commands.commandregistry.icommandexecutedargs.args.md

commands.commandregistry.icommandexecutedargs.id.md

commands.commandregistry.icommandexecutedargs.md

commands.commandregistry.icommandexecutedargs.result.md

commands.commandregistry.icommandoptions.caption.md

commands.commandregistry.icommandoptions.classname.md

commands.commandregistry.icommandoptions.dataset.md

commands.commandregistry.icommandoptions.execute.md

commands.commandregistry.icommandoptions.icon.md

commands.commandregistry.icommandoptions.iconclass.md

commands.commandregistry.icommandoptions.iconlabel.md

commands.commandregistry.icommandoptions.isenabled.md

commands.commandregistry.icommandoptions.istoggled.md

commands.commandregistry.icommandoptions.isvisible.md

commands.commandregistry.icommandoptions.label.md

commands.commandregistry.icommandoptions.md

commands.commandregistry.icommandoptions.mnemonic.md

commands.commandregistry.icommandoptions.usage.md