p-map-series

Map over promises serially

Usage no npm install needed!

<script type="module">
  import pMapSeries from 'https://cdn.skypack.dev/p-map-series';
</script>

README

p-map-series

Map over promises serially

Useful as a side-effect mapper. Use p-map if you don't need side-effects, as it's concurrent.

Install

$ npm install p-map-series

Usage

import pMapSeries from 'p-map-series';

const keywords = [
    getTopKeyword() //=> Promise
    'rainbow',
    'pony'
];

let scores = [];

const mapper = async keyword => {
    const score = await fetchScore(keyword);
    scores.push(score);
    return {keyword, score};
});

console.log(await pMapSeries(keywords, mapper));
/*
[
    {
        keyword: 'unicorn',
        score: 99
    },
    {
        keyword: 'rainbow',
        score: 70
    },
    {
        keyword: 'pony',
        score: 79
    }
]
*/

API

pMapSeries(input, mapper)

Returns a Promise that is fulfilled when all promises in input and ones returned from mapper are fulfilled, or rejects if any of the promises reject. The fulfilled value is an Array of the mapper created promises fulfillment values.

input

Type: Iterable<Promise | unknown>

Mapped over serially in the mapper function.

mapper(element, index)

Type: Function

Expected to return a value. If it's a Promise, it's awaited before continuing with the next iteration.

Related


Get professional support for this package with a Tidelift subscription
Tidelift helps make open source sustainable for maintainers while giving companies
assurances about security, maintenance, and licensing for their dependencies.