patrickroberts / iterablex

Lazy method chaining iterables

iterablex

Lazy method chaining iterables

About

This library exports a function to create a lazy iterable from any iterable. The return value's type will depend on what operations the original iterable supports:

• A ContiguousRange for any TypedArray
• A RandomAccessRange for any iterable not above implementing a constant-time .at(index) method
• A ForwardRange for any iterable not above that can be iterated without consuming the input
• An InputRange for any other iterable not above

A BidirectionalRange may be returned by some of the lazy methods for ContiguousRange, RandomAccessRange, and itself, to indicate the returned iterable supports lazy .toReversed() without buffering.

Lazy methods:

• .drop(count: number)
• .entries()
• .filter(predicate: (value, index) => boolean)
• .flatMap(callback: (value, index) => iterable)
• .map(callback: (value, index) => any)
• .scan(callback: (previous, value, index) => next, initial?)
• .slice(begin?, end?)
• .take(count: number)
• .toReversed()
• .toSorted(compare?: (a, b) => number)

Eager methods:

• .at(index: number): value?
• .every(predicate: (value, index) => boolean): boolean
• .find(predicate: (value, index) => boolean): value?
• .findIndex(predicate: (value, index) => boolean): number
• .findLast(predicate: (value, index) => boolean): value?
• .findLastIndex(predicate: (value, index) => boolean): number
• .first(predicate?: (value, index) => boolean): value?
• .forEach(callback: (value, index) => void): void
• .includes(value, fromIndex?: number): boolean
• .indexOf(value, fromIndex?: number): number
• .last(predicate?: (value, index) => boolean): value?
• .lastIndexOf(value, fromIndex?: number): number
• .reduce(callback: (previous, value, index) => next, initial?)
• .some(predicate: (value, index) => boolean): boolean
• .toArray(): array

...and more to come!

TODO

• Tests (and bugfixes)
• More documentation
• More methods