Merge pull request #68 from emberjs/default-utilites-from-window

default globals implementation

Author: ef4

__tests__/tests.ts

@@ -12,6 +12,7 @@ import sinon from 'sinon';
 import { ExtendedPluginBuilder } from '../src/js-utils';
 import 'code-equality-assertions/jest';
 import { Preprocessor } from 'content-tag';
+import { ALLOWED_GLOBALS } from '../src/scope-locals';
 
 describe('htmlbars-inline-precompile', function () {
   // eslint-disable-next-line @typescript-eslint/no-var-requires
@@ -1901,6 +1902,37 @@ describe('htmlbars-inline-precompile', function () {
       `);
     });
 
+    describe('implements RFC#1070: default globals', function () {
+      for (let name of ALLOWED_GLOBALS) {
+        it(`${name}: allowed`, async function () {
+          plugins = [
+            [
+              HTMLBarsInlinePrecompile,
+              {
+                compiler,
+                targetFormat: 'hbs',
+              },
+            ],
+          ];
+
+          let transformed = await transform(
+            `import { template } from '@ember/template-compiler'; 
+         const data = {};
+         export default template('{{${name} data}}', { eval: function() { return eval(arguments[0]) } })
+        `
+          );
+
+          expect(transformed).toEqualCode(`
+        import { precompileTemplate } from "@ember/template-compilation";
+        import { setComponentTemplate } from "@ember/component";
+        import templateOnly from "@ember/component/template-only";
+        const data = {};
+        export default setComponentTemplate(precompileTemplate('{{${name} data}}', { strictMode: true, scope: () => ({ ${name}, data }) }), templateOnly());
+      `);
+        });
+      }
+    });
+
     // You might think this would be confusing style, and you'd be correct. But
     // that's what the lint rules are for. When it comes to correctness, we need
     // our scope to behave like real Javascript, and Javascript doesn't care

src/scope-locals.ts

@@ -12,6 +12,76 @@ import { ASTPluginEnvironment, NodeVisitor } from '@glimmer/syntax';
 import { astNodeHasBinding } from './hbs-utils';
 import { readOnlyArray } from './read-only-array';
 
+/**
+ * RFC: https://github.com/emberjs/rfcs/pull/1070
+ *
+ * Criteria for inclusion in this list:
+ *
+ *   Any of:
+ *     - begins with an uppercase letter
+ *     - guaranteed to never be added to glimmer as a keyword (e.g.: globalThis)
+ *
+ *   And:
+ *     - must not need new to invoke
+ *     - must not require lifetime management (e.g.: setTimeout)
+ *     - must not be a single-word lower-case API, because of potential collision with future new HTML elements
+ *     - if the API is a function, the return value should not be a promise
+ *     - must be one one of these lists:
+ *        - https://tc39.es/ecma262/#sec-global-object
+ *        - https://tc39.es/ecma262/#sec-function-properties-of-the-global-object
+ *        - https://html.spec.whatwg.org/multipage/nav-history-apis.html#window
+ *        - https://html.spec.whatwg.org/multipage/indices.html#all-interfaces
+ *        - https://html.spec.whatwg.org/multipage/webappapis.html
+ */
+export const ALLOWED_GLOBALS = new Set([
+  // ////////////////
+  // namespaces
+  // ////////////////
+  //   TC39
+  'globalThis',
+  'Atomics',
+  'JSON',
+  'Math',
+  'Reflect',
+  //   WHATWG
+  'localStorage',
+  'sessionStorage',
+  // ////////////////
+  // functions / utilities
+  // ////////////////
+  //   TC39
+  'isNaN',
+  'isFinite',
+  'parseInt',
+  'parseFloat',
+  'decodeURI',
+  'decodeURIComponent',
+  'encodeURI',
+  'encodeURIComponent',
+  //   WHATWG
+  'postMessage',
+  'structuredClone',
+  // ////////////////
+  // new-less Constructors (still functions)
+  // ////////////////
+  //   TC39
+  'Array', // different behavior from (array)
+  'BigInt',
+  'Boolean',
+  'Date',
+  'Number',
+  'Object', // different behavior from (hash)
+  'String',
+  // ////////////////
+  // Values
+  // ////////////////
+  //   TC39
+  'Infinity',
+  'NaN',
+  //   WHATWG
+  'isSecureContext',
+]);
+
 /*
     `mode` refers to the implicit and explicit formats defined here:
 
@@ -72,7 +142,7 @@ export class ScopeLocals {
 
   #isInJsScope(hbsName: string, jsPath: NodePath) {
     let jsName = this.#mapping[hbsName] ?? hbsName;
-    return ['globalThis'].includes(jsName) || jsPath.scope.getBinding(jsName);
+    return ALLOWED_GLOBALS.has(jsName) || jsPath.scope.getBinding(jsName);
   }
 
   // this AST transform discovers all possible upvars in HBS that refer to valid