gatsby/dist/utils/merge-gatsby-config.js

Blazing fast modern site generator for React

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
exports.__esModule = true;
exports.mergeGatsbyConfig = void 0;
var _uniq2 = _interopRequireDefault(require("lodash/uniq"));
var _merge2 = _interopRequireDefault(require("lodash/merge"));
const howToMerge = {
  /**
   * pick a truthy value by default.
   * This makes sure that if a single value is defined, that one it used.
   * We prefer the "right" value, because the user's config will be "on the right"
   */
  byDefault: (a, b) => b || a,
  siteMetadata: (objA, objB) => (0, _merge2.default)({}, objA, objB),
  // plugins are concatenated and uniq'd, so we don't get two of the same plugin value
  plugins: (a = [], b = []) => a.concat(b),
  mapping: (objA, objB) => (0, _merge2.default)({}, objA, objB)
};

/**
 * Defines how a theme object is merged with the user's config
 */
const mergeGatsbyConfig = (a, b) => {
  // a and b are gatsby configs, If they have keys, that means there are values to merge
  const allGatsbyConfigKeysWithAValue = (0, _uniq2.default)(Object.keys(a).concat(Object.keys(b)));

  // reduce the array of mergable keys into a single gatsby config object
  const mergedConfig = allGatsbyConfigKeysWithAValue.reduce((config, gatsbyConfigKey) => {
    // choose a merge function for the config key if there's one defined,
    // otherwise use the default value merge function
    const mergeFn = howToMerge[gatsbyConfigKey] || howToMerge.byDefault;
    return {
      ...config,
      [gatsbyConfigKey]: mergeFn(a[gatsbyConfigKey], b[gatsbyConfigKey])
    };
  }, {});

  // return the fully merged config
  return mergedConfig;
};
exports.mergeGatsbyConfig = mergeGatsbyConfig;
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