@async-generators/map
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    0.1.0 • Public • Published

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    map items of an iterable sequence to another value

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    Usage

    package requires a system that supports async-iteration, either natively or via down-compiling

    Install

    npm install @async-generators/map --save
    yarn add @async-generators/map
    

    This package's main entry points to a commonjs distribution.

    Additionally, the module entry points to a es2015 distribution, which can be used by build systems, such as webpack, to directly use es2015 modules.

    Api

    map(source, selector)

    map() iterates the source and yields await selector(item, index)

    source must have a [Symbol.asyncIterator] or [Symbol.iterator] property. If both are present only [Symbol.asyncIterator] is used.

    selector(item, index) should return the object to yield. The second parameter is the index of the item as it appeared in the source sequence.

    Example

    example.js

    const map = require('@async-generators/map').default;
     
    async function main() {
     
      async function* source() {
        yield "hello"; yield "world";
      }
     
      let mapped = map(source(),
        (x, i) => {
          return {
            value: x.toString(),
            index: i
          }
        });
     
      for await (let item of mapped) {
        console.log(item);
      }
    }
     
    main();

    Execute with the latest node.js:

    node --harmony-async-iteration example.js
    

    output:

    { value: 'hello', index: 0 }
    { value: 'world', index: 1 }
    

    Typescript

    This library is fully typed and can be imported using:

    import filter from '@async-generators/map');

    It is also possible to directly execute your properly configured typescript with ts-node:

    ts-node --harmony_async_iteration foo.ts
    

    Install

    npm i @async-generators/map

    DownloadsWeekly Downloads

    376

    Version

    0.1.0

    License

    MIT

    Last publish

    Collaborators

    • meirionhughes