Update core 8.3.0

web/core/scripts/js/babel-es6-build.js

@@ -0,0 +1,54 @@
+/**
+ * @file
+ *
+ * Compile *.es6.js files to ES5.
+ *
+ * @internal This file is part of the core javascript build process and is only
+ * meant to be used in that context.
+ */
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const babel = require('babel-core');
+const glob = require('glob');
+
+// Logging human-readable timestamp.
+const log = function (message) {
+  // eslint-disable-next-line no-console
+  console.log(`[${new Date().toTimeString().slice(0, 8)}] ${message}`);
+};
+
+function addSourceMappingUrl(code, loc) {
+  return code + '\n\n//# sourceMappingURL=' + path.basename(loc);
+}
+
+const changedOrAdded = (filePath) => {
+  babel.transformFile(filePath, {
+    sourceMaps: true,
+    comments: false
+  }, function (err, result) {
+    const fileName = filePath.slice(0, -7);
+    // we've requested for a sourcemap to be written to disk
+    let mapLoc = `${fileName}.js.map`;
+
+    fs.writeFile(mapLoc, JSON.stringify(result.map));
+    fs.writeFile(`${fileName}.js`, addSourceMappingUrl(result.code, mapLoc));
+
+    log(`'${filePath}' is being processed.`);
+  });
+};
+
+const fileMatch = './**/*.es6.js';
+const globOptions = {
+  ignore: 'node_modules/**'
+};
+const processFiles = (error, filePaths) => {
+  if (error) {
+    process.exitCode = 1;
+  }
+  filePaths.forEach(changedOrAdded);
+};
+glob(fileMatch, globOptions, processFiles);
+process.exitCode = 0;