filter-dependent

Filters a list of files, leaving only those which transitively dependent on any of the files from the second list.

Why this package was written?

Because I can! But also, because I failed to find anything like that, except jest-resolve-dependencies, which is not exactly what I need, and also have not very good algorithmic complexity (btw mine is O(n), where n is a number of nodes in a dependency graph fragment between sources and targers).

What problem it solves?

Similiar to changedSince – it allows you to find all files dependent from other files. And, therefore, skip other files.

For example, you can:

• Find all test files, which affected by git changeset, and should be running.
• Find all affected .stories.js files to build storybook only with affected components.

By doing that, you skip non-affected files and speed up your CI/build.

Features

• Supports js, jsx, ts, tsx.
• Fast.
• Resolves all symlinks to real filenames.
• Skip node_modules by default.

Example

Lets say we have four files:

• a.js depends on b.js and c.js
• b.js depends on d.js

Then:

import filterDependent from 'filter-dependent'

const filteredFiles = filterDependent([
    './a.js',
    './b.js',
    './c.js',
    './d.js',
], [
    'a.js',
    'c.js',
])

// → ['/abs/path/to/a.js', '/abs/path/to/b.js', '/abs/path/to/c.js']
// because `d.js` does not depend on `c.js` nor `a.js`

API

import filterDependent from 'filter-dependent'

const filteredFiles = filterDependent(sources, targets, options)

Where

sources – an array of file paths to be filtered. targets – an array of file paths to be used for filtering out sources. options.filter – function, which will be called on each found file (including sources and targers) to filter out some. (f: string) => f.indexOf('node_modules') === -1 && !f.endsWith('.css') by default. options.onMiss – function, which will be called instead of throwing an error. Arguments are: filename and dep – absolute path of processing file and unresolved dependendy in it

note: filter-dependent fails on first unresolved dependency (by default).