notes/node_modules/stylelint/lib/getConfigForFile.js

/* @flow */
"use strict"
const augmentConfigFull = require("./augmentConfig").augmentConfigFull
const configurationError = require("./utils/configurationError")
const path = require("path")

module.exports = function (
  stylelint/*: stylelint$internalApi*/,
  searchPath/*:: ?: string*/
)/*: Promise<?{ config: stylelint$config, filepath: string }>*/ {
  searchPath = searchPath || process.cwd()

  const optionsConfig = stylelint._options.config

  if (optionsConfig !== undefined) {
    const cached = stylelint._specifiedConfigCache.get(optionsConfig)
    if (cached) return cached

    // stylelint._fullExplorer (cosmiconfig) is already configured to
    // run augmentConfigFull; but since we're making up the result here,
    // we need to manually run the transform
    const augmentedResult = augmentConfigFull(stylelint, {
      config: optionsConfig,
      // Add the extra path part so that we can get the directory without being
      // confused
      filepath: path.join(process.cwd(), "argument-config"),
    })
    stylelint._specifiedConfigCache.set(optionsConfig, augmentedResult)
    return augmentedResult
  }

  return stylelint._fullExplorer.load(searchPath, stylelint._options.configFile).then(config => {
    // If no config was found, try looking from process.cwd
    if (!config) return stylelint._fullExplorer.load(process.cwd())
    return config
  }).then(config => {
    if (!config) {
      const ending = searchPath ? ` for ${searchPath}` : ""
      throw configurationError(`No configuration provided${ending}`)
    }
    return config
  })
}