FuncType - v0.60.3
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    Interface CollectionOps<A, Self>

    Operations specific to collections (List, Set, etc.). These operations don't make sense for single-value containers.

    interface CollectionOps<out A extends Type, Self> {
        get head(): A | undefined;
        get headOption(): Option<A>;
        get init(): Self;
        get last(): A | undefined;
        get lastOption(): Option<A>;
        get tail(): Self;
        drop(n: number): Self;
        dropRight(n: number): Self;
        dropWhile(p: (a: A) => boolean): Self;
        flatten<B>(): Self;
        fold<B>(initial: B, fn: (acc: B, a: A) => B): B;
        take(n: number): Self;
        takeRight(n: number): Self;
        takeWhile(p: (a: A) => boolean): Self;
        toArray<B = A>(): B[];
    }

    Type Parameters

    • out A extends Type

      The element type

    • Self

      The collection type itself for proper return types

    Hierarchy (View Summary)

    Index

    Accessors

    head headOption init last lastOption tail

    Methods

    drop dropRight dropWhile flatten fold take takeRight takeWhile toArray

    Accessors

    • get head(): A | undefined

      Gets the first element of the collection.

      Returns A | undefined

    • get headOption(): Option<A>

      Gets the first element wrapped in Option.

      Returns Option<A>

    • get init(): Self

      Gets all elements except the last.

      Returns Self

    • get last(): A | undefined

      Gets the last element of the collection.

      Returns A | undefined

    • get lastOption(): Option<A>

      Gets the last element wrapped in Option.

      Returns Option<A>

    • get tail(): Self

      Gets all elements except the first.

      Returns Self

    Methods

    • Drops the first n elements from the collection.

      Parameters

      • n: number

      Returns Self

    • Drops the last n elements from the collection.

      Parameters

      • n: number

      Returns Self

    • Drops elements from the start while the predicate is true.

      Parameters

      • p: (a: A) => boolean

      Returns Self

    • Flattens a collection of collections into a single collection.

      Type Parameters

      • B

      Returns Self

    • Left-associative fold over all elements using an initial value and combining function. Unlike foldLeft (which is curried), this provides a convenient uncurried signature.

      Type Parameters

      • B

      Parameters

      • initial: B

        The initial accumulator value

      • fn: (acc: B, a: A) => B

        A function that combines the accumulator with each element

      Returns B

      The final accumulated value

      List([1, 2, 3]).fold(0, (acc, x) => acc + x) // 6

    • Takes the first n elements from the collection.

      Parameters

      • n: number

      Returns Self

    • Takes the last n elements from the collection.

      Parameters

      • n: number

      Returns Self

    • Takes elements from the start while the predicate is true.

      Parameters

      • p: (a: A) => boolean

      Returns Self

    • Converts the collection to an array.

      Type Parameters

      • B = A

      Returns B[]

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