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Interface: Array<T>

Type Parameters​

T​

T

Indexable​

[n: number]: T

Properties​

[unscopables]​

readonly [unscopables]: object

Is an object whose properties have the value 'true' when they will be absent when used in a 'with' statement.

Index Signature​

[key: number]: boolean

find?​

optional find?: boolean

findIndex?​

optional findIndex?: boolean

fill?​

optional fill?: boolean

copyWithin?​

optional copyWithin?: boolean

[iterator]?​

optional [iterator]?: boolean

entries?​

optional entries?: boolean

keys?​

optional keys?: boolean

values?​

optional values?: boolean

[unscopables]?​

readonly optional [unscopables]?: boolean

Is an object whose properties have the value 'true' when they will be absent when used in a 'with' statement.

includes?​

optional includes?: boolean

flatMap?​

optional flatMap?: boolean

flat?​

optional flat?: boolean

length?​

optional length?: boolean

Gets or sets the length of the array. This is a number one higher than the highest index in the array.

toString?​

optional toString?: boolean

toLocaleString?​

optional toLocaleString?: boolean

pop?​

optional pop?: boolean

push?​

optional push?: boolean

concat?​

optional concat?: boolean

join?​

optional join?: boolean

reverse?​

optional reverse?: boolean

shift?​

optional shift?: boolean

slice?​

optional slice?: boolean

sort?​

optional sort?: boolean

splice?​

optional splice?: boolean

unshift?​

optional unshift?: boolean

indexOf?​

optional indexOf?: boolean

lastIndexOf?​

optional lastIndexOf?: boolean

every?​

optional every?: boolean

some?​

optional some?: boolean

forEach?​

optional forEach?: boolean

map?​

optional map?: boolean

filter?​

optional filter?: boolean

reduce?​

optional reduce?: boolean

reduceRight?​

optional reduceRight?: boolean

length​

length: number

Gets or sets the length of the array. This is a number one higher than the highest index in the array.

Methods​

find()​

Call Signature​

find<S>(predicate, thisArg?): S

Returns the value of the first element in the array where predicate is true, and undefined otherwise.

Type Parameters​
S​

S

Parameters​
predicate​

(value, index, obj) => value is S

find calls predicate once for each element of the array, in ascending order, until it finds one where predicate returns true. If such an element is found, find immediately returns that element value. Otherwise, find returns undefined.

thisArg?​

any

If provided, it will be used as the this value for each invocation of predicate. If it is not provided, undefined is used instead.

Returns​

S

Call Signature​

find(predicate, thisArg?): T

Parameters​
predicate​

(value, index, obj) => unknown

thisArg?​

any

Returns​

T

Call Signature​

find<U>(predicate): U

Type Parameters​
U​

U

Parameters​
predicate​

(value, index, obj) => value is U

Returns​

U

findIndex()​

findIndex(predicate, thisArg?): number

Returns the index of the first element in the array where predicate is true, and -1 otherwise.

Parameters​

predicate​

(value, index, obj) => unknown

find calls predicate once for each element of the array, in ascending order, until it finds one where predicate returns true. If such an element is found, findIndex immediately returns that element index. Otherwise, findIndex returns -1.

thisArg?​

any

If provided, it will be used as the this value for each invocation of predicate. If it is not provided, undefined is used instead.

Returns​

number

fill()​

fill(value, start?, end?): this

Changes all array elements from start to end index to a static value and returns the modified array

Parameters​

value​

T

value to fill array section with

start?​

number

index to start filling the array at. If start is negative, it is treated as length+start where length is the length of the array.

end?​

number

index to stop filling the array at. If end is negative, it is treated as length+end.

Returns​

this

copyWithin()​

copyWithin(target, start, end?): this

Returns the this object after copying a section of the array identified by start and end to the same array starting at position target

Parameters​

target​

number

If target is negative, it is treated as length+target where length is the length of the array.

start​

number

If start is negative, it is treated as length+start. If end is negative, it is treated as length+end.

end?​

number

If not specified, length of the this object is used as its default value.

Returns​

this

[iterator]()​

[iterator](): ArrayIterator<T>

Iterator

Returns​

ArrayIterator<T>

entries()​

entries(): ArrayIterator<[number, T]>

Returns an iterable of key, value pairs for every entry in the array

Returns​

ArrayIterator<[number, T]>

keys()​

keys(): ArrayIterator<number>

Returns an iterable of keys in the array

Returns​

ArrayIterator<number>

values()​

values(): ArrayIterator<T>

Returns an iterable of values in the array

Returns​

ArrayIterator<T>

includes()​

includes(searchElement, fromIndex?): boolean

Determines whether an array includes a certain element, returning true or false as appropriate.

Parameters​

searchElement​

T

The element to search for.

fromIndex?​

number

The position in this array at which to begin searching for searchElement.

Returns​

boolean

flatMap()​

flatMap<U, This>(callback, thisArg?): U[]

Calls a defined callback function on each element of an array. Then, flattens the result into a new array. This is identical to a map followed by flat with depth 1.

Type Parameters​

U​

U

This​

This = undefined

Parameters​

callback​

(this, value, index, array) => U | readonly U[]

A function that accepts up to three arguments. The flatMap method calls the callback function one time for each element in the array.

thisArg?​

This

An object to which the this keyword can refer in the callback function. If thisArg is omitted, undefined is used as the this value.

Returns​

U[]

flat()​

flat<A, D>(this, depth?): FlatArray<A, D>[]

Returns a new array with all sub-array elements concatenated into it recursively up to the specified depth.

Type Parameters​

A​

A

D​

D extends number = 1

Parameters​

this​

A

depth?​

D

The maximum recursion depth

Returns​

FlatArray<A, D>[]

toString()​

toString(): string

Returns a string representation of an array.

Returns​

string

toLocaleString()​

Call Signature​

toLocaleString(): string

Returns a string representation of an array. The elements are converted to string using their toLocaleString methods.

Returns​

string

Call Signature​

toLocaleString(locales, options?): string

Parameters​
locales​

string | string[]

options?​

NumberFormatOptions & DateTimeFormatOptions

Returns​

string

pop()​

pop(): T

Removes the last element from an array and returns it. If the array is empty, undefined is returned and the array is not modified.

Returns​

T

push()​

push(...items): number

Appends new elements to the end of an array, and returns the new length of the array.

Parameters​

items​

...T[]

New elements to add to the array.

Returns​

number

concat()​

Call Signature​

concat(...items): T[]

Combines two or more arrays. This method returns a new array without modifying any existing arrays.

Parameters​
items​

...ConcatArray<T>[]

Additional arrays and/or items to add to the end of the array.

Returns​

T[]

Call Signature​

concat(...items): T[]

Combines two or more arrays. This method returns a new array without modifying any existing arrays.

Parameters​
items​

...(T | ConcatArray<T>)[]

Additional arrays and/or items to add to the end of the array.

Returns​

T[]

join()​

join(separator?): string

Adds all the elements of an array into a string, separated by the specified separator string.

Parameters​

separator?​

string

A string used to separate one element of the array from the next in the resulting string. If omitted, the array elements are separated with a comma.

Returns​

string

reverse()​

reverse(): T[]

Reverses the elements in an array in place. This method mutates the array and returns a reference to the same array.

Returns​

T[]

shift()​

shift(): T

Removes the first element from an array and returns it. If the array is empty, undefined is returned and the array is not modified.

Returns​

T

slice()​

slice(start?, end?): T[]

Returns a copy of a section of an array. For both start and end, a negative index can be used to indicate an offset from the end of the array. For example, -2 refers to the second to last element of the array.

Parameters​

start?​

number

The beginning index of the specified portion of the array. If start is undefined, then the slice begins at index 0.

end?​

number

The end index of the specified portion of the array. This is exclusive of the element at the index 'end'. If end is undefined, then the slice extends to the end of the array.

Returns​

T[]

sort()​

sort(compareFn?): this

Sorts an array in place. This method mutates the array and returns a reference to the same array.

Parameters​

compareFn?​

(a, b) => number

Function used to determine the order of the elements. It is expected to return a negative value if the first argument is less than the second argument, zero if they're equal, and a positive value otherwise. If omitted, the elements are sorted in ascending, ASCII character order.

[11,2,22,1].sort((a, b) => a - b)

Returns​

this

splice()​

Call Signature​

splice(start, deleteCount?): T[]

Removes elements from an array and, if necessary, inserts new elements in their place, returning the deleted elements.

Parameters​
start​

number

The zero-based location in the array from which to start removing elements.

deleteCount?​

number

The number of elements to remove.

Returns​

T[]

An array containing the elements that were deleted.

Call Signature​

splice(start, deleteCount, ...items): T[]

Removes elements from an array and, if necessary, inserts new elements in their place, returning the deleted elements.

Parameters​
start​

number

The zero-based location in the array from which to start removing elements.

deleteCount​

number

The number of elements to remove.

items​

...T[]

Elements to insert into the array in place of the deleted elements.

Returns​

T[]

An array containing the elements that were deleted.

unshift()​

unshift(...items): number

Inserts new elements at the start of an array, and returns the new length of the array.

Parameters​

items​

...T[]

Elements to insert at the start of the array.

Returns​

number

indexOf()​

indexOf(searchElement, fromIndex?): number

Returns the index of the first occurrence of a value in an array, or -1 if it is not present.

Parameters​

searchElement​

T

The value to locate in the array.

fromIndex?​

number

The array index at which to begin the search. If fromIndex is omitted, the search starts at index 0.

Returns​

number

lastIndexOf()​

lastIndexOf(searchElement, fromIndex?): number

Returns the index of the last occurrence of a specified value in an array, or -1 if it is not present.

Parameters​

searchElement​

T

The value to locate in the array.

fromIndex?​

number

The array index at which to begin searching backward. If fromIndex is omitted, the search starts at the last index in the array.

Returns​

number

every()​

Call Signature​

every<S>(predicate, thisArg?): this is S[]

Determines whether all the members of an array satisfy the specified test.

Type Parameters​
S​

S

Parameters​
predicate​

(value, index, array) => value is S

A function that accepts up to three arguments. The every method calls the predicate function for each element in the array until the predicate returns a value which is coercible to the Boolean value false, or until the end of the array.

thisArg?​

any

An object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.

Returns​

this is S[]

Call Signature​

every(predicate, thisArg?): boolean

Determines whether all the members of an array satisfy the specified test.

Parameters​
predicate​

(value, index, array) => unknown

A function that accepts up to three arguments. The every method calls the predicate function for each element in the array until the predicate returns a value which is coercible to the Boolean value false, or until the end of the array.

thisArg?​

any

An object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.

Returns​

boolean

some()​

some(predicate, thisArg?): boolean

Determines whether the specified callback function returns true for any element of an array.

Parameters​

predicate​

(value, index, array) => unknown

A function that accepts up to three arguments. The some method calls the predicate function for each element in the array until the predicate returns a value which is coercible to the Boolean value true, or until the end of the array.

thisArg?​

any

An object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.

Returns​

boolean

forEach()​

forEach(callbackfn, thisArg?): void

Performs the specified action for each element in an array.

Parameters​

callbackfn​

(value, index, array) => void

A function that accepts up to three arguments. forEach calls the callbackfn function one time for each element in the array.

thisArg?​

any

An object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.

Returns​

void

map()​

map<U>(callbackfn, thisArg?): U[]

Calls a defined callback function on each element of an array, and returns an array that contains the results.

Type Parameters​

U​

U

Parameters​

callbackfn​

(value, index, array) => U

A function that accepts up to three arguments. The map method calls the callbackfn function one time for each element in the array.

thisArg?​

any

An object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.

Returns​

U[]

filter()​

Call Signature​

filter<S>(predicate, thisArg?): S[]

Returns the elements of an array that meet the condition specified in a callback function.

Type Parameters​
S​

S

Parameters​
predicate​

(value, index, array) => value is S

A function that accepts up to three arguments. The filter method calls the predicate function one time for each element in the array.

thisArg?​

any

An object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.

Returns​

S[]

Call Signature​

filter(predicate, thisArg?): T[]

Returns the elements of an array that meet the condition specified in a callback function.

Parameters​
predicate​

(value, index, array) => unknown

A function that accepts up to three arguments. The filter method calls the predicate function one time for each element in the array.

thisArg?​

any

An object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.

Returns​

T[]

reduce()​

Call Signature​

reduce(callbackfn): T

Calls the specified callback function for all the elements in an array. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.

Parameters​
callbackfn​

(previousValue, currentValue, currentIndex, array) => T

A function that accepts up to four arguments. The reduce method calls the callbackfn function one time for each element in the array.

Returns​

T

Call Signature​

reduce(callbackfn, initialValue): T

Parameters​
callbackfn​

(previousValue, currentValue, currentIndex, array) => T

initialValue​

T

Returns​

T

Call Signature​

reduce<U>(callbackfn, initialValue): U

Calls the specified callback function for all the elements in an array. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.

Type Parameters​
U​

U

Parameters​
callbackfn​

(previousValue, currentValue, currentIndex, array) => U

A function that accepts up to four arguments. The reduce method calls the callbackfn function one time for each element in the array.

initialValue​

U

If initialValue is specified, it is used as the initial value to start the accumulation. The first call to the callbackfn function provides this value as an argument instead of an array value.

Returns​

U

reduceRight()​

Call Signature​

reduceRight(callbackfn): T

Calls the specified callback function for all the elements in an array, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.

Parameters​
callbackfn​

(previousValue, currentValue, currentIndex, array) => T

A function that accepts up to four arguments. The reduceRight method calls the callbackfn function one time for each element in the array.

Returns​

T

Call Signature​

reduceRight(callbackfn, initialValue): T

Parameters​
callbackfn​

(previousValue, currentValue, currentIndex, array) => T

initialValue​

T

Returns​

T

Call Signature​

reduceRight<U>(callbackfn, initialValue): U

Calls the specified callback function for all the elements in an array, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.

Type Parameters​
U​

U

Parameters​
callbackfn​

(previousValue, currentValue, currentIndex, array) => U

A function that accepts up to four arguments. The reduceRight method calls the callbackfn function one time for each element in the array.

initialValue​

U

If initialValue is specified, it is used as the initial value to start the accumulation. The first call to the callbackfn function provides this value as an argument instead of an array value.

Returns​

U

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