[BUGFIX lts] build: Turn off sourcemaps for TS-to-ES compilation

broccoli/packages.js

@@ -87,7 +87,11 @@ module.exports.getPackagesES = function getPackagesES() {
     include: ['**/*.ts'],
   });
 
-  let typescriptCompiled = typescript(debugTree(typescriptContents, `get-packages-es:ts:input`));
+  let typescriptCompiled = typescript(debugTree(typescriptContents, `get-packages-es:ts:input`), {
+    compilerOptions: {
+      sourceMap: false,
+    },
+  });
 
   let debuggedCompiledTypescript = debugTree(typescriptCompiled, `get-packages-es:ts:output`);
 

tests/node/sourcemap-test.js

@@ -0,0 +1,27 @@
+var fs = require('fs');
+
+QUnit.module('sourcemap validation', function() {
+  var assets = ['ember.debug', 'ember.prod', 'ember.min'];
+
+  assets.forEach(asset => {
+    QUnit.test(`${asset} has only a single sourcemaps comment`, function(assert) {
+      var jsPath = `dist/${asset}.js`;
+      assert.ok(fs.existsSync(jsPath));
+
+      var contents = fs.readFileSync(jsPath, 'utf-8');
+      var num = count(contents, '//# sourceMappingURL=');
+      assert.equal(num, 1);
+    });
+  });
+});
+
+function count(source, find) {
+  var num = 0;
+
+  var i = -1;
+  while ((i = source.indexOf(find, i + 1)) !== -1) {
+    num += 1;
+  }
+
+  return num;
+}