Vfile-is NPM | npm.io

vfile-is

vfile utility to check if a file passes a test.

What is this?

This package is a small utility that checks that a file is a certain file.

When should I use this?

Use this small utility if you find yourself repeating code for checking files.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install vfile-is

In Deno with esm.sh:

import {is} from 'https://esm.sh/vfile-is@3'

In browsers with esm.sh:

<script type="module">
  import {is} from 'https://esm.sh/vfile-is@3?bundle'
</script>

Use

import {VFile} from 'to-vfile'
import {is} from 'vfile-is'

is(undefined, '.js') // => false
is({}, '.js') // => false

is(new VFile({path: 'index.js'}), '.js') // => true
is(new VFile({path: 'index.js'}), '.md') // => false
is(new VFile({path: 'index.js'}), 'index.js') // => true
is(new VFile({path: 'index.js'}), 'readme.md') // => false
is(new VFile({path: 'index.js'}), '*.js') // => true
is(new VFile({path: 'index.js'}), '*.md') // => false

is(new VFile({path: 'index.js'}), {stem: 'index'}) // => true
is(new VFile({path: 'index.js'}), {stem: 'readme'}) // => false

is(new VFile({path: 'index.js'}), {stem: {prefix: 'in'}}) // => true
is(new VFile({path: 'index.js'}), {stem: {prefix: 're'}}) // => false
is(new VFile({path: 'index.js'}), {stem: {suffix: 'ex'}}) // => true
is(new VFile({path: 'index.js'}), {stem: {suffix: 'me'}}) // => false

API

This package exports the identifiers convert and is. There is no default export.

`convert(check)`

Create an assertion from check.

Parameters

check (Check, optional) — check

Returns

Assertion (Assert).

`is(file, check?)`

Check if file is a specific file.

Converts check to an assertion and calls that assertion with file. If you’re doing a lot of checks, use convert.

Parameters

file (unknown) — file to check (typically VFile)
check (Check, optional) — check

Returns

Whether file is a file and matches check (boolean).

`Assert`

Check that a file is a vfile and passes a test (TypeScript type).

Parameters

file (unknown) — file to check (typically VFile)

Returns

Whether file is a file and matches a bound check (boolean).

`Check`

Different ways to check for a specific file (TypeScript type).

if check is a glob string, checks if that glob matches file.path
if check is a normal string, checks if that is file.basename or file.extname
if check is a function, checks whether that yields true when called
if check is a normal object, checks if the given file matches the CheckFields
if check is an array, all tests in it must pass

Type

type Check =
  | Array<CheckFields | CheckFile | string | null | undefined>
  | CheckFields
  | CheckFile
  | string
  | null
  | undefined

`CheckFields`

Object describing fields to values (TypeScript type).

Each key is a field in the file and each value is:

boolean — whether the field exists or not
object — start (prefix) and/or end (suffix) of the field
string — exact value of that field

Type

type FieldPartial = {
  prefix?: string | null | undefined
  suffix?: string | null | undefined
}

type CheckFields = Record<
  string,
  FieldPartial | boolean | string | null | undefined
>

`CheckFile`

Check if a file passes a custom test (TypeScript type).

Parameters

file (VFile) — file to check

Returns

Whether the test passed for this file (boolean, optional).

Types

This package is fully typed with TypeScript. It exports the additional types Assert, Check, CheckFields, and CheckFile.

Compatibility

Projects maintained by the unified collective are compatible with maintained versions of Node.js.

When we cut a new major release, we drop support for unmaintained versions of Node. This means we try to keep the current release line, vfile-is@^3, compatible with Node.js 16.