Mapz NPM | npm.io

mapz

Functional map with sugar.

What is this?

This is a tiny package that, in combination with zwitch, helps with ASTs.

When should I use this?

You can use this package when you want to map one AST to another, or check an AST.

Install

This package is ESM only. In Node.js (version 14.14+, 16.0+), install with npm:

npm install mapz

In Deno with esm.sh:

import {mapz} from 'https://esm.sh/mapz@2'

In browsers with esm.sh:

<script type="module">
  import {mapz} from 'https://esm.sh/mapz@2?bundle'
</script>

Use

import {mapz} from 'mapz'

const map = mapz(fn, {key: 'children', gapless: true})

map({type: 'something', children: [1, 2, 3]}) // => ['Hi, 2', 'Hi, 3']

function fn(value) {
  return value > 1 ? 'Hi, ' + value + '.' : null
}

API

This package exports the identifier mapz. There is no default export.

`mapz(fn[, options])`

Functional map with sugar.

Wraps the supplied fn, which handles one value, so that it accepts multiple values, calling fn for each and returning all results.

If options is a string, it’s treated as {key: options}.

`options.gapless`

Whether to filter out null and undefined results (boolean, default: false).

`options.key`

If a key (string, optional) is given, and an object supplied to the wrapped fn, values at that object’s key field are mapped and the object, instead of the values, is given to fn as a last parameter. If a key is given and an array is passed to the wrapped fn, no value is given to fn as a last parameter.

Returns

See map(values) (Function).

`map(values)`

Call the bound fn for all values. If a key is bound, values can be an object. See options.key for more info.

Returns

Values returned by fn (Array<unknown>). If gapless is true, null orundefined results are not returned by map.

`fn(value, parent?)`

Handle one value. If key is set and an array is given, no parent is passed.

Returns

Any value (unknown).

Types

This package is fully typed with TypeScript. It exports the additional type Options.

Compatibility

This package is at least compatible with all maintained versions of Node.js. As of now, that is Node.js 14.14+ and 16.0+. It also works in Deno and modern browsers.