validate.js

'use strict';

const {
  difference,
  forEach,
  isArray,
  isBoolean,
  isFunction,
  isPlainObject,
  isRegExp,
  isString,
  keys,
} = require('lodash');

const rules = {
  // hook
  camelCase: 'boolean|string',
  devMode: 'boolean',
  extensions: 'array|string',
  ignore: 'function|regex|string',
  preprocessCss: 'function',
  processCss: 'function',
  processorOpts: 'object',
  // plugins
  append: 'array',
  prepend: 'array',
  use: 'array',
  createImportedName: 'function',
  generateScopedName: 'function|string',
  hashPrefix: 'string',
  mode: 'string',
  rootDir: 'string',
  noCache: 'boolean',
};

const tests = {
  array: isArray,
  boolean: isBoolean,
  function: isFunction,
  object: isPlainObject,
  regex: isRegExp,
  string: isString,
};

module.exports = function validate(options) {
  const unknownOptions = difference(keys(options), keys(rules));
  if (unknownOptions.length)
    throw new Error(`unknown arguments: ${unknownOptions.join(', ')}.`);

  forEach(rules, (types, rule) => {
    if (typeof options[rule] === 'undefined')
      return;

    if (!types.split('|').some(type => tests[type](options[rule])))
      throw new TypeError(`should specify ${types} as ${rule}`);
  });
};