gatsby-plugin-page-creator/watch-collection-builder.js

Gatsby plugin that automatically creates pages from React components in specified directories

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
exports.__esModule = true;
exports.watchCollectionBuilder = watchCollectionBuilder;
var _chokidar = _interopRequireDefault(require("chokidar"));
var _collectionExtractQueryString = require("./collection-extract-query-string");
/*
 * When a user is developing, they may want to mess around with the collectionQuery or renaming
 * the file, this function watches the file and if the query strings change, we delete the old
 * pages and then re-run the collection builder.
 *
 * TODO: Can we reuse the watcher from gatsby-node to avoid creating new watchers? or use a different
 *       library that is _better_ at watching files with a single global internal watcher, like watchpack.
 */
function watchCollectionBuilder(absolutePath, previousQueryString, paths, actions, reporter, rerunCollectionBuilder) {
  const watcher = _chokidar.default.watch(absolutePath).on(`change`, () => {
    const queryString = (0, _collectionExtractQueryString.collectionExtractQueryString)(absolutePath, reporter);

    // if the users is changing the query to generate the pages, we need to delete the old pages
    // and re-run the builder.
    if (queryString !== previousQueryString) {
      // 1.  close the old watcher, because when we rerun the collection builder
      //     it'll create a new watcher. Just easier to code that way.
      watcher.close();

      // 2.  Make sure to delete all the old pages
      paths.forEach(path => actions.deletePage({
        path,
        component: absolutePath
      }));

      // 3.  Then run it again!
      rerunCollectionBuilder();
    }
  });
}