generateTasks.js

'use strict'

const micromatch = require('micromatch')
const path = require('path')

const debug = require('debug')('lint-staged:gen-tasks')

/**
 * Test if `child` path is inside `parent` path
 * https://stackoverflow.com/a/45242825
 *
 * @param {String} parent
 * @param {String} child
 * @returns {Boolean}
 */
const isPathInside = (parent, child) => {
  const relative = path.relative(parent, child)
  return relative && !relative.startsWith('..') && !path.isAbsolute(relative)
}

/**
 * Generates all task commands, and filelist
 *
 * @param {object} options
 * @param {Object} [options.config] - Task configuration
 * @param {Object} [options.cwd] - Current working directory
 * @param {boolean} [options.gitDir] - Git root directory
 * @param {boolean} [options.files] - Staged filepaths
 * @param {boolean} [options.relative] - Whether filepaths to should be relative to gitDir
 * @returns {Promise}
 */
module.exports = function generateTasks({
  config,
  cwd = process.cwd(),
  gitDir,
  files,
  relative = false
}) {
  debug('Generating linter tasks')
  return Object.entries(config).map(([pattern, commands]) => {
    const isParentDirPattern = pattern.startsWith('../')
    const fileList = micromatch(
      files
        // Only worry about children of the CWD unless the pattern explicitly
        // specifies that it concerns a parent directory.
        .filter(file => {
          if (isParentDirPattern) return true
          const absolutePath = path.resolve(gitDir, file)
          return isPathInside(cwd, absolutePath)
        }),
      pattern,
      {
        cwd,
        dot: true,
        // If pattern doesn't look like a path, enable `matchBase` to
        // match against filenames in every directory. This makes `*.js`
        // match both `test.js` and `subdirectory/test.js`.
        matchBase: !pattern.includes('/'),
        posixSlashes: true
      }
    ).map(file =>
      // Return absolute path after the filter is run
      relative ? file : cwd + '/' + file
    )

    const task = { pattern, commands, fileList }
    debug('Generated task: \n%O', task)

    return task
  })
}