seq.mjs

A JavaScript module that allows iterators to use array-like methods.

There is also an asynchronous version: https://github.com/haiix/aseq

Installation

npm install @haiix/seq

Usage

import seq from '@haiix/seq'

Examples

1. By passing the natural number N to the seq function, an iterator is created that increments between 0 and N. You can use array-like methods (map, join, etc.) on the created iterator.

   seq(3).join() // "0,1,2"

   seq(4).map(x => x + 1).join() // "1,2,3,4"

2. You can pass an iterable object (with the [Symbol.iterator] method) to the seq function.

   seq([10, 20, 30]).map(x => x + 1).join() // "11,21,31"

3. There are no methods implemented that rewrite themselves. If you want to use those methods, convert them to arrays once.

   //seq(5).reverse() // Error
   Array.from(seq(5)).reverse() // [4, 3, 2, 1, 0]

4. In this example, the array is not created internally, and the map and filter operations for terms after 5 found in indexOf are not performed.

   seq(100).map(x => x * 2).filter(x => x % 3 > 0).indexOf(16) // 5

5. The iterator created by the seq function can be used in a for-of statement. Use in processing with side effects.

   for (const n of seq(3)) {
     console.log(n) // 0, 1, 2
   }

   for (const elem of seq(3).map(n => document.createElement('input'))) {
     document.body.appendChild(elem)
   }