notes/node_modules/stylelint/lib/normalizeRuleSettings.js

/* @flow */
"use strict"
const _ = require("lodash")
const rules = require("./rules")

// Rule settings can take a number of forms, e.g.
// a. "rule-name": null
// b. "rule-name": [null, ...]
// c. "rule-name": primaryOption
// d. "rule-name": [primaryOption]
// e. "rule-name": [primaryOption, secondaryOption]
// Where primaryOption can be anything: primitive, Object, or Array.
//
// This function normalizes all the possibilities into the
// standard form: [primaryOption, secondaryOption]
// Except in the cases with null, a & b, in which case
// null is returned
module.exports = function (
  rawSettings/*: stylelint$configRuleSettings*/,
  ruleName/*: string*/,
  // If primaryOptionArray is not provided, we try to get it from the
  // rules themselves, which will not work for plugins
  primaryOptionArray/*:: ?: boolean*/
)/*: [any, Object] | Array<any | [any, Object]> | null*/ {
  if (rawSettings === null) {
    return null
  }

  if (!Array.isArray(rawSettings)) {
    return [rawSettings]
  }
  // Everything below is an array ...

  if (rawSettings[0] === null) {
    return null
  }

  // This cursed rule needs a special case
  if (ruleName === "declaration-block-properties-order") {
    if (rawSettings[0] === "alphabetical") {
      return rawSettings
    }
    if (typeof rawSettings[0] === "string") {
      return [rawSettings]
    }
  }

  if (primaryOptionArray === undefined) {
    const rule = rules[ruleName]
    primaryOptionArray = _.get(rule, "primaryOptionArray")
  }

  if (!primaryOptionArray) {
    return rawSettings
  }
  // Everything below is a rule that CAN have an array for a primary option ...
  // (they might also have something else, e.g. rule-properties-order can
  // have the string "alphabetical")

  if (rawSettings.length === 1 && Array.isArray(rawSettings[0])) {
    return rawSettings
  }

  if (rawSettings.length === 2 && !_.isPlainObject(rawSettings[0]) && _.isPlainObject(rawSettings[1])) {
    return rawSettings
  }

  return [rawSettings]
}