Ensure output dir exists, return Promise

lib/utils/extract.js

@@ -1,8 +1,9 @@
 const fs = require('fs-extra');
 const app = require('express')();
 const compression = require('compression');
+const mkdirp = require('mkdirp');
 const sapper = require('../index.js');
-const static = require('serve-static');
+const serve = require('serve-static');
 const Spider = require('node-spider');
 const path = require('path');
 
@@ -106,6 +107,12 @@ function getChunkFiles() {
  */
 module.exports = function(includeUrls = null, excludeUrls = null,
     apiPrefix = '/api', extractionDir = OUTPUT_DIR) {
+
+  // Clean the output directory and copy assets in.
+  fs.removeSync(extractionDir);
+  mkdirp.sync(extractionDir);
+  fs.copySync('assets', extractionDir);
+
   // Set up the server.
 
   // this allows us to do e.g. `fetch('/api/blog')` on the server
@@ -117,14 +124,10 @@ module.exports = function(includeUrls = null, excludeUrls = null,
 
   app.use(compression({ threshold: 0 }));
 
-  app.use(static('assets'));
+  app.use(serve('assets'));
 
   app.use(sapper());
 
-  // Clean the output directory and copy assets in.
-  fs.removeSync(extractionDir);
-  fs.copySync('assets', extractionDir);
-
   // If exclude URLs are set, normalize them.
   if (excludeUrls == null) excludeUrls = [];
   excludeUrls = excludeUrls.map((url) => getFullUrl(url));
@@ -133,9 +136,11 @@ module.exports = function(includeUrls = null, excludeUrls = null,
   // scraper. The program automatically exits after all the static pages have
   // been scraped from the server that are accessible from the root page (`/`).
   const extractedFiles = []; // keep track of extracted files.
-  const server = app.listen(PORT, () => {
-    console.log(`listening on port ${PORT} and beginning extraction`);
-    return new Promise((resolve, reject) => {
+
+  return new Promise((resolve, reject) => {
+    const server = app.listen(PORT, () => {
+      console.log(`listening on port ${PORT} and beginning extraction`);
+
       const spider = new Spider({
         concurrent: 5,
         delay: 0,
@@ -228,4 +233,4 @@ module.exports = function(includeUrls = null, excludeUrls = null,
       }
     });
   });
-}
+};