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Function: fuse()

fuse<ElementType>(iterable: IterableResolvable<ElementType>): IterableIterator<ElementType>

Creates an iterator which ends after the first done result from the original iterator.

After an iterator returns a done result, future calls may or may not yield additional results again. This function adapts an iterator, ensuring that after a done result is given, it will always return a done result forever.

Type Parameters​

Type Parameter
ElementType

Parameters​

ParameterTypeDescription
iterableIterableResolvable<ElementType>An iterator to fuse.

Returns​

IterableIterator<ElementType>

Example​

import { fuse } from '@sapphire/iterator-utilities';

const iterable = {
  state: 0,
  next() {
    const value = this.state;
    this.state += 1;

    return value % 2 === 0 //
      ? { done: false, value }
      : { done: true, value: undefined };
  }
};

// We can see our iterator going back and forth
assert(iterable.next(), { done: false, value: 0 });
assert(iterable.next(), { done: true, value: undefined });
assert(iterable.next(), { done: false, value: 2 });
assert(iterable.next(), { done: true, value: undefined });

// However, once we fuse it...
const fused = fuse(iterable);

assert(fused.next(), { done: false, value: 4 });
assert(fused.next(), { done: true, value: undefined });

// It will always return a `done` result after the first time
assert(fused.next(), { done: true, value: undefined });
assert(fused.next(), { done: true, value: undefined });
assert(fused.next(), { done: true, value: undefined });

Defined in​

projects/utilities/packages/iterator-utilities/src/lib/fuse.ts:47