@bolt/prerender-spa-plugin/index.js

Bolt Design System fork of the Webpack Prerender SPA Plugin

const path = require('path');

const Prerenderer = require('@prerenderer/prerenderer');

const PuppeteerRenderer = require('@bolt/uikit-prerenderer');

const {
  minify
} = require('html-minifier');

function PrerenderSPAPlugin(...args) {
  const rendererOptions = {}; // Primarily for backwards-compatibility.

  this._options = {}; // Normal args object.

  if (args.length === 1) {
    this._options = args[0] || {}; // Backwards-compatibility with v2
  } else {
    console.warn("[prerender-spa-plugin] You appear to be using the v2 argument-based configuration options. It's recommended that you migrate to the clearer object-based configuration system.\nCheck the documentation for more information.");
    let staticDir, routes;
    args.forEach(arg => {
      if (typeof arg === 'string') staticDir = arg;else if (Array.isArray(arg)) routes = arg;else if (typeof arg === 'object') this._options = arg;
    });
    staticDir ? this._options.staticDir = staticDir : null;
    routes ? this._options.routes = routes : null;
  } // Backwards compatiblity with v2.


  if (this._options.captureAfterDocumentEvent) {
    console.warn('[prerender-spa-plugin] captureAfterDocumentEvent has been renamed to renderAfterDocumentEvent and should be moved to the renderer options.');
    rendererOptions.renderAfterDocumentEvent = this._options.captureAfterDocumentEvent;
  }

  if (this._options.captureAfterElementExists) {
    console.warn('[prerender-spa-plugin] captureAfterElementExists has been renamed to renderAfterElementExists and should be moved to the renderer options.');
    rendererOptions.renderAfterElementExists = this._options.captureAfterElementExists;
  }

  if (this._options.captureAfterTime) {
    console.warn('[prerender-spa-plugin] captureAfterTime has been renamed to renderAfterTime and should be moved to the renderer options.');
    rendererOptions.renderAfterTime = this._options.captureAfterTime;
  }

  this._options.server = this._options.server || {};
  this._options.renderer = this._options.renderer || new PuppeteerRenderer(Object.assign({}, {
    headless: true
  }, rendererOptions));

  if (this._options.postProcessHtml) {
    console.warn('[prerender-spa-plugin] postProcessHtml should be migrated to postProcess! Consult the documentation for more information.');
  }
}

PrerenderSPAPlugin.prototype.apply = function (compiler) {
  const compilerFS = compiler.outputFileSystem; // From https://github.com/ahmadnassri/mkdirp-promise/blob/master/lib/index.js

  const mkdirp = function (dir, opts) {
    return new Promise((resolve, reject) => {
      compilerFS.mkdirp(dir, opts, (err, made) => err === null ? resolve(made) : reject(err));
    });
  };

  const afterEmit = (compilation, done) => {
    const PrerendererInstance = new Prerenderer(this._options);
    PrerendererInstance.initialize().then(() => {
      return PrerendererInstance.renderRoutes(this._options.routes || []);
    }) // Backwards-compatibility with v2 (postprocessHTML should be migrated to postProcess)
    .then(renderedRoutes => this._options.postProcessHtml ? renderedRoutes.map(renderedRoute => {
      const processed = this._options.postProcessHtml(renderedRoute);

      if (typeof processed === 'string') renderedRoute.html = processed;else renderedRoute = processed;
      return renderedRoute;
    }) : renderedRoutes) // Run postProcess hooks.
    .then(renderedRoutes => this._options.postProcess ? Promise.all(renderedRoutes.map(renderedRoute => this._options.postProcess(renderedRoute))) : renderedRoutes) // Check to ensure postProcess hooks returned the renderedRoute object properly.
    .then(renderedRoutes => {
      const isValid = renderedRoutes.every(r => typeof r === 'object');

      if (!isValid) {
        throw new Error('[prerender-spa-plugin] Rendered routes are empty, did you forget to return the `context` object in postProcess?');
      }

      return renderedRoutes;
    }) // Minify html files if specified in config.
    .then(renderedRoutes => {
      if (!this._options.minify) return renderedRoutes;
      renderedRoutes.forEach(route => {
        route.html = minify(route.html, this._options.minify);
      });
      return renderedRoutes;
    }) // Calculate outputPath if it hasn't been set already.
    .then(renderedRoutes => {
      renderedRoutes.forEach(rendered => {
        if (!rendered.outputPath) {
          rendered.outputPath = path.join(this._options.outputDir || this._options.staticDir, rendered.route, 'index.html');
        }
      });
      return renderedRoutes;
    }) // Create dirs and write prerendered files.
    .then(processedRoutes => {
      const promises = Promise.all(processedRoutes.map(processedRoute => {
        return mkdirp(path.dirname(processedRoute.outputPath)).then(() => {
          return new Promise((resolve, reject) => {
            compilerFS.writeFile(processedRoute.outputPath, processedRoute.html.trim(), err => {
              if (err) // eslint-disable-next-line prefer-promise-reject-errors
                reject(`[prerender-spa-plugin] Unable to write rendered route to file "${processedRoute.outputPath}" \n ${err}.`);else resolve();
            });
          });
        }).catch(err => {
          if (typeof err === 'string') {
            err = `[prerender-spa-plugin] Unable to create directory ${path.dirname(processedRoute.outputPath)} for route ${processedRoute.route}. \n ${err}`;
          }

          throw err;
        });
      }));
      return promises;
    }).then(r => {
      PrerendererInstance.destroy();
      done();
    }).catch(err => {
      PrerendererInstance.destroy();
      const msg = '[prerender-spa-plugin] Unable to prerender all routes!';
      console.error(msg);
      compilation.errors.push(new Error(msg));
      done();
    });
  };

  if (compiler.hooks) {
    const plugin = {
      name: 'PrerenderSPAPlugin'
    };
    compiler.hooks.afterEmit.tapAsync(plugin, afterEmit);
  } else {
    compiler.plugin('after-emit', afterEmit);
  }
};

PrerenderSPAPlugin.PuppeteerRenderer = PuppeteerRenderer;
module.exports = PrerenderSPAPlugin;