Iterame

About

Iterame is an iterator library for transforming a collection in a single iteration.

Installation

You can install iterame using npm:

$ npm install iterame

Usage

import { iterame, map } from 'iterame'

function * range (from, to) {
  while (from < to) { yield from++ }
}

// [0, 2, 4, 6, 8]
iterame(range(0, 5)).pipe(map(value => value * 2)).toArray()

// 0
iterame(range(0, 5)).pipe(map(value => value * 2)).first()

// 1
iterame(range(0, 5)).pipe(map(value => value * 2), at(2)).value()

Operators

• at

// 1
iterame(range(0, 5)).pipe(at(1)).value()

• every

// true
iterame(range(0, 5)).pipe(every(v => v >= 0)).value()

• filter

// [3, 4]
iterame(range(0, 5)).pipe(filter(v => v > 2)).toArray()

• find

// 4
iterame(range(0, 5)).pipe(find(v => v > 3)).value()

• map

// [0, 2, 4, 6, 8]
iterame(range(0, 5)).pipe(map(value => value * 2)).toArray()

• slice

// [1, 2, 3]
iterame(range(0, 5)).pipe(slice(1, 3)).toArray()

• some

// false
iterame(range(0, 5)).pipe(some(v => v === 10)).value()

• take

// [0, 1, 2]
iterame(range(0, 5)).pipe(take(3)).toArray()

How to create your own operator

Operators must fulfil this type

type Operator<T, K> = (iterator: Iterable<T>) => Generator<K, void>

For example, to create an operator called add to add a value at the end of the initial iterator:

function add<T> (value: T) {
  return function * (iterator: Iterable<T>) {
    for (const v of iterator) {
      yield v
    }
    yield value
  }
}

// [0, 1, 2, 3, 4, 10]
iterame(range(0, 5)).pipe(add(10))

Motivation

To facilitate the use of structure as map or set and at the same time learn more about the iterators