An array which functions as a set. It guarantees unique elements and provides set functions for comparisons

Type Parameters

  • T

Hierarchy

  • Array
    • ASet

Constructors

  • Array to create set from, duplicate values will be removed

    Type Parameters

    • T

    Parameters

    • elements: T[] = []

      Elements which will be added to set

    Returns ASet<T>

Properties

[unscopables]: {
    [unscopables]?: boolean;
    length?: boolean;
    [iterator]?: any;
    at?: any;
    concat?: any;
    copyWithin?: any;
    entries?: any;
    every?: any;
    fill?: any;
    filter?: any;
    find?: any;
    findIndex?: any;
    findLast?: any;
    findLastIndex?: any;
    flat?: any;
    flatMap?: any;
    forEach?: any;
    includes?: any;
    indexOf?: any;
    join?: any;
    keys?: any;
    lastIndexOf?: any;
    map?: any;
    pop?: any;
    push?: any;
    reduce?: any;
    reduceRight?: any;
    reverse?: any;
    shift?: any;
    slice?: any;
    some?: any;
    sort?: any;
    splice?: any;
    toLocaleString?: any;
    toReversed?: any;
    toSorted?: any;
    toSpliced?: any;
    toString?: any;
    unshift?: any;
    values?: any;
    with?: any;
}

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

Type declaration

  • Optional Readonly[unscopables]?: boolean

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

  • Optionallength?: boolean

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

length: number

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

[species]: ArrayConstructor

Accessors

  • get size(): number
  • Number of elements in set

    Returns number

Methods

  • Iterator

    Returns ArrayIterator<any>

  • Add elements to set if unique

    Parameters

    • Rest...items: T[]

    Returns ASet<T>

  • Returns the item located at the specified index.

    Parameters

    • index: number

      The zero-based index of the desired code unit. A negative index will count back from the last item.

    Returns any

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

    Parameters

    • Rest...items: ConcatArray<any>[]

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

    Returns any[]

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

    Parameters

    • Rest...items: any[]

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

    Returns any[]

  • 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.

    • Optionalend: number

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

    Returns this

  • Delete elements from set

    Parameters

    • Rest...items: T[]

      Elements that will be deleted

    Returns ASet<T>

  • Create list of elements this set has which the comparison set does not

    Parameters

    • set: ASet<T>

      Set to compare against

    Returns ASet<T>

    Different elements

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

    Returns ArrayIterator<[number, any]>

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

    Type Parameters

    • S extends any

    Parameters

    • predicate: ((value: any, index: number, array: any[]) => 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.

        • (value, index, array): value is S
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns value is S

    • OptionalthisArg: 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[]

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

    Parameters

    • predicate: ((value: any, index: number, array: any[]) => 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.

        • (value, index, array): unknown
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns unknown

    • OptionalthisArg: 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

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

    Parameters

    • value: any

      value to fill array section with

    • Optionalstart: 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.

    • Optionalend: number

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

    Returns this

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

    Type Parameters

    • S extends any

    Parameters

    • predicate: ((value: any, index: number, array: any[]) => 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.

        • (value, index, array): value is S
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns value is S

    • OptionalthisArg: 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[]

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

    Parameters

    • predicate: ((value: any, index: number, array: any[]) => unknown)

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

        • (value, index, array): unknown
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns unknown

    • OptionalthisArg: 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 any[]

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

    Type Parameters

    • S extends any

    Parameters

    • predicate: ((value: any, index: number, obj: any[]) => 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.

        • (value, index, obj): value is S
        • Parameters

          • value: any
          • index: number
          • obj: any[]

          Returns value is S

    • OptionalthisArg: 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 undefined | S

  • Parameters

    • predicate: ((value: any, index: number, obj: any[]) => unknown)
        • (value, index, obj): unknown
        • Parameters

          • value: any
          • index: number
          • obj: any[]

          Returns unknown

    • OptionalthisArg: any

    Returns any

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

    Parameters

    • predicate: ((value: any, index: number, obj: any[]) => 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.

        • (value, index, obj): unknown
        • Parameters

          • value: any
          • index: number
          • obj: any[]

          Returns unknown

    • OptionalthisArg: 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

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

    Type Parameters

    • S extends any

    Parameters

    • predicate: ((value: any, index: number, array: any[]) => value is S)

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

        • (value, index, array): value is S
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns value is S

    • OptionalthisArg: 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 undefined | S

  • Parameters

    • predicate: ((value: any, index: number, array: any[]) => unknown)
        • (value, index, array): unknown
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns unknown

    • OptionalthisArg: any

    Returns any

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

    Parameters

    • predicate: ((value: any, index: number, array: any[]) => unknown)

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

        • (value, index, array): unknown
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns unknown

    • OptionalthisArg: 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

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

    Type Parameters

    • A
    • D extends number = 1

    Parameters

    • this: A
    • Optionaldepth: D

      The maximum recursion depth

    Returns FlatArray<A, D>[]

  • 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
    • This = undefined

    Parameters

    • callback: ((this: This, value: any, index: number, array: any[]) => 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.

        • (this, value, index, array): U | readonly U[]
        • Parameters

          • this: This
          • value: any
          • index: number
          • array: any[]

          Returns U | readonly U[]

    • OptionalthisArg: 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[]

  • Performs the specified action for each element in an array.

    Parameters

    • callbackfn: ((value: any, index: number, array: any[]) => void)

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

        • (value, index, array): void
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns void

    • OptionalthisArg: 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

  • Check if set includes element

    Parameters

    • el: T

      Element to look for

    Returns boolean

    True if element was found, false otherwise

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

    Parameters

    • searchElement: any

      The element to search for.

    • OptionalfromIndex: number

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

    Returns boolean

  • Find index number of element, or -1 if it doesn't exist. Matches by equality not reference

    Parameters

    • search: T

      Element to find

    • OptionalfromIndex: number

      Starting index position

    Returns number

    Element index number or -1 if missing

  • Create list of elements this set has in common with the comparison set

    Parameters

    • set: ASet<T>

      Set to compare against

    Returns ASet<T>

    Set of common elements

  • Check if this set has no elements in common with the comparison set

    Parameters

    • set: ASet<T>

      Set to compare against

    Returns boolean

    True if nothing in common, false otherwise

  • Check if all elements in this set are included in the comparison set

    Parameters

    • set: ASet<T>

      Set to compare against

    Returns boolean

    True if all elements are included, false otherwise

  • Check if all elements from comparison set are included in this set

    Parameters

    • set: ASet<T>

      Set to compare against

    Returns boolean

    True if all elements are included, false otherwise

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

    Parameters

    • Optionalseparator: 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

  • Returns an iterable of keys in the array

    Returns ArrayIterator<number>

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

    Parameters

    • searchElement: any

      The value to locate in the array.

    • OptionalfromIndex: 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

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

    Type Parameters

    • U

    Parameters

    • callbackfn: ((value: any, index: number, array: any[]) => U)

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

        • (value, index, array): U
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns U

    • OptionalthisArg: 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[]

  • 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 any

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

    Parameters

    • Rest...items: any[]

      New elements to add to the array.

    Returns number

  • 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: any, currentValue: any, currentIndex: number, array: any[]) => any)

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

        • (previousValue, currentValue, currentIndex, array): any
        • Parameters

          • previousValue: any
          • currentValue: any
          • currentIndex: number
          • array: any[]

          Returns any

    Returns any

  • Parameters

    • callbackfn: ((previousValue: any, currentValue: any, currentIndex: number, array: any[]) => any)
        • (previousValue, currentValue, currentIndex, array): any
        • Parameters

          • previousValue: any
          • currentValue: any
          • currentIndex: number
          • array: any[]

          Returns any

    • initialValue: any

    Returns any

  • 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

    Parameters

    • callbackfn: ((previousValue: U, currentValue: any, currentIndex: number, array: any[]) => U)

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

        • (previousValue, currentValue, currentIndex, array): U
        • Parameters

          • previousValue: U
          • currentValue: any
          • currentIndex: number
          • array: any[]

          Returns U

    • 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

  • 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: any, currentValue: any, currentIndex: number, array: any[]) => any)

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

        • (previousValue, currentValue, currentIndex, array): any
        • Parameters

          • previousValue: any
          • currentValue: any
          • currentIndex: number
          • array: any[]

          Returns any

    Returns any

  • Parameters

    • callbackfn: ((previousValue: any, currentValue: any, currentIndex: number, array: any[]) => any)
        • (previousValue, currentValue, currentIndex, array): any
        • Parameters

          • previousValue: any
          • currentValue: any
          • currentIndex: number
          • array: any[]

          Returns any

    • initialValue: any

    Returns any

  • 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

    Parameters

    • callbackfn: ((previousValue: U, currentValue: any, currentIndex: number, array: any[]) => U)

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

        • (previousValue, currentValue, currentIndex, array): U
        • Parameters

          • previousValue: U
          • currentValue: any
          • currentIndex: number
          • array: any[]

          Returns U

    • 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

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

    Returns any[]

  • 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 any

  • 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

    • Optionalstart: number

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

    • Optionalend: 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 any[]

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

    Parameters

    • predicate: ((value: any, index: number, array: any[]) => 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.

        • (value, index, array): unknown
        • Parameters

          • value: any
          • index: number
          • array: any[]

          Returns unknown

    • OptionalthisArg: 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

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

    Parameters

    • OptionalcompareFn: ((a: any, b: any) => 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)
      
        • (a, b): number
        • Parameters

          • a: any
          • b: any

          Returns number

    Returns this

  • 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.

    • OptionaldeleteCount: number

      The number of elements to remove.

    Returns any[]

    An array containing the elements that were deleted.

  • 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.

    • Rest...items: any[]

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

    Returns any[]

    An array containing the elements that were deleted.

  • Create list of elements that are only in one set but not both (XOR)

    Parameters

    • set: ASet<T>

      Set to compare against

    Returns ASet<any>

    New set of unique elements

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

    Returns string

  • Parameters

    • locales: string | string[]
    • Optionaloptions: NumberFormatOptions & DateTimeFormatOptions

    Returns string

  • Returns a copy of an array with its elements reversed.

    Returns any[]

  • Returns a copy of an array with its elements sorted.

    Parameters

    • OptionalcompareFn: ((a: any, b: any) => 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].toSorted((a, b) => a - b) // [1, 2, 11, 22]
      
        • (a, b): number
        • Parameters

          • a: any
          • b: any

          Returns number

    Returns any[]

  • Copies an array and removes elements and, if necessary, inserts new elements in their place. Returns the copied array.

    Parameters

    • start: number

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

    • deleteCount: number

      The number of elements to remove.

    • Rest...items: any[]

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

    Returns any[]

    The copied array.

  • Copies an array and removes elements while returning the remaining elements.

    Parameters

    • start: number

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

    • OptionaldeleteCount: number

      The number of elements to remove.

    Returns any[]

    A copy of the original array with the remaining elements.

  • Returns a string representation of an array.

    Returns string

  • Create joined list of elements included in this & the comparison set

    Parameters

    Returns ASet<any>

    New set of both previous sets combined

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

    Parameters

    • Rest...items: any[]

      Elements to insert at the start of the array.

    Returns number

  • Returns an iterable of values in the array

    Returns ArrayIterator<any>

  • Copies an array, then overwrites the value at the provided index with the given value. If the index is negative, then it replaces from the end of the array.

    Parameters

    • index: number

      The index of the value to overwrite. If the index is negative, then it replaces from the end of the array.

    • value: any

      The value to write into the copied array.

    Returns any[]

    The copied array with the updated value.

  • Creates an array from an array-like object.

    Type Parameters

    • T

    Parameters

    • arrayLike: ArrayLike<T>

      An array-like object to convert to an array.

    Returns T[]

  • Creates an array from an iterable object.

    Type Parameters

    • T
    • U

    Parameters

    • arrayLike: ArrayLike<T>

      An array-like object to convert to an array.

    • mapfn: ((v: T, k: number) => U)

      A mapping function to call on every element of the array.

        • (v, k): U
        • Parameters

          • v: T
          • k: number

          Returns U

    • OptionalthisArg: any

      Value of 'this' used to invoke the mapfn.

    Returns U[]

  • Creates an array from an iterable object.

    Type Parameters

    • T

    Parameters

    • iterable: Iterable<T, any, any> | ArrayLike<T>

      An iterable object to convert to an array.

    Returns T[]

  • Creates an array from an iterable object.

    Type Parameters

    • T
    • U

    Parameters

    • iterable: Iterable<T, any, any> | ArrayLike<T>

      An iterable object to convert to an array.

    • mapfn: ((v: T, k: number) => U)

      A mapping function to call on every element of the array.

        • (v, k): U
        • Parameters

          • v: T
          • k: number

          Returns U

    • OptionalthisArg: any

      Value of 'this' used to invoke the mapfn.

    Returns U[]

  • Creates an array from an async iterator or iterable object.

    Type Parameters

    • T

    Parameters

    • iterableOrArrayLike: AsyncIterable<T, any, any> | Iterable<T | PromiseLike<T>, any, any> | ArrayLike<T | PromiseLike<T>>

      An async iterator or array-like object to convert to an array.

    Returns Promise<T[]>

  • Creates an array from an async iterator or iterable object.

    Type Parameters

    • T
    • U

    Parameters

    • iterableOrArrayLike: AsyncIterable<T, any, any> | Iterable<T, any, any> | ArrayLike<T>

      An async iterator or array-like object to convert to an array.

    • mapFn: ((value: Awaited<T>) => U)
        • (value): U
        • Parameters

          • value: Awaited<T>

          Returns U

    • OptionalthisArg: any

      Value of 'this' used when executing mapfn.

    Returns Promise<Awaited<U>[]>

  • Parameters

    • arg: any

    Returns arg is any[]

  • Returns a new array from a set of elements.

    Type Parameters

    • T

    Parameters

    • Rest...items: T[]

      A set of elements to include in the new array object.

    Returns T[]