Remove Object.fromEntries

It's not supported across our current browser matrix.

That said, our matrix is pretty outdated and we should see about
updating it.

For example, Object.fromEntries was added in Chrome 73 (March 2019), but
we currently build on Chrome 70.

build/broccoli/strip-glimmer-utilities.js

@@ -28,7 +28,7 @@ module.exports = function (jsTree) {
       [
         stripGlimmerUtils,
         {
-          bindings: ['expect', 'unwrap', 'castToSimple', 'castToBrowser'],
+          bindings: ['expect', 'unwrap', 'castToSimple', 'castToBrowser', 'asPresentArray'],
           source: '@glimmer/util',
         },
       ],
@@ -82,8 +82,37 @@ function stripFlags(glimmerUtils) {
     },
     'nuke-vm-metadata',
   ]);
+  glimmerUtils.push([
+    nuke,
+    {
+      source: '@glimmer/util',
+      delegate: replaceEmpties,
+    },
+    'replace-empties',
+  ]);
 }
 
+/**
+ * @param {string} bindingName
+ * @param {import("@babel/traverse").NodePath} path
+ * @param {import("@babel/types")} t
+ */
+function replaceEmpties(bindingName, path, t) {
+  if (
+    bindingName === 'EMPTY_STRING_ARRAY' ||
+    bindingName === 'EMPTY_NUMBER_ARRAY' ||
+    bindingName === 'EMPTY_ARRAY'
+  ) {
+    path.parentPath.replaceWith(t.arrayExpression());
+  }
+}
+
+/**
+ *
+ * @param {string} bindingName
+ * @param {import("@babel/traverse").NodePath} path
+ * @param {import("@babel/types")} t
+ */
 function removeMetaData(bindingName, path, t) {
   if (bindingName === 'METADATA') {
     path.parentPath.replaceWith(t.nullLiteral());

package.json

@@ -59,7 +59,11 @@
     "@babel/core": "^7.21.8",
     "@babel/plugin-transform-modules-commonjs": "^7.21.5",
     "@babel/preset-env": "^7.21.5",
+    "@babel/traverse": "^7.21.5",
+    "@babel/types": "^7.21.5",
     "@glimmer/env": "0.1.7",
+    "@rollup/plugin-terser": "^0.4.1",
+    "@types/babel__traverse": "^7.18.5",
     "@types/node": "^18.16.3",
     "@types/qunit": "^2.19.5",
     "@typescript-eslint/eslint-plugin": "^5.59.2",
@@ -88,11 +92,11 @@
     "eslint-config-prettier": "^8.8.0",
     "eslint-import-resolver-typescript": "^3.5.5",
     "eslint-plugin-import": "^2.27.5",
-    "eslint-plugin-unused-imports": "^2.0.0",
     "eslint-plugin-n": "^15.7.0",
     "eslint-plugin-prettier": "^4.2.1",
     "eslint-plugin-qunit": "^7.3.4",
     "eslint-plugin-simple-import-sort": "^10.0.0",
+    "eslint-plugin-unused-imports": "^2.0.0",
     "execa": "^7.1.1",
     "glob": "^10.2.2",
     "js-yaml": "^4.1.0",
@@ -104,7 +108,6 @@
     "rimraf": "^5.0.0",
     "rollup": "^3.21.3",
     "rollup-plugin-sourcemaps": "^0.6.3",
-    "@rollup/plugin-terser": "^0.4.1",
     "semver": "^7.5.0",
     "testem-failure-only-reporter": "^1.0.0",
     "toml": "^3.0.0",

packages/@glimmer/syntax/test/support.ts

@@ -1,4 +1,4 @@
-import { entries } from '@glimmer/util';
+import { isObject, mapObject } from '@glimmer/util';
 
 import { AST, preprocess as parse, PreprocessOptions } from '..';
 
@@ -7,15 +7,11 @@ function normalizeNode(obj: AST.Node | Array<AST.Node>): AST.Node | Array<AST.No
 }
 
 function normalizeValue<T extends AST.Node | AST.Node[] | unknown>(obj: T): T {
-  if (obj && typeof obj === 'object') {
+  if (isObject(obj)) {
     if (Array.isArray(obj)) {
       return obj.map(normalizeValue) as T;
     } else {
-      return Object.fromEntries(
-        entries(obj).flatMap(([key, value]) =>
-          key === 'loc' ? [] : [[key, normalizeValue(value)]]
-        )
-      ) as T;
+      return mapObject(obj, (value) => normalizeValue(value)) as T;
     }
   } else {
     return obj;

packages/@glimmer/util/index.ts

@@ -10,7 +10,7 @@ export {
   isSerializationFirstNode,
   SERIALIZATION_FIRST_NODE_STRING,
 } from './lib/is-serialization-first-node';
-export { assign, entries, fillNulls, values } from './lib/object-utils';
+export { assign, entries, fillNulls, mapObject, values } from './lib/object-utils';
 export * from './lib/platform-utils';
 export * from './lib/present';
 export {

packages/@glimmer/util/lib/object-utils.ts

@@ -1,3 +1,5 @@
+import { dict } from './collections';
+
 export let assign = Object.assign;
 
 export function fillNulls<T>(count: number): T[] {
@@ -19,3 +21,19 @@ export type ObjectEntry<D extends object> = { [P in keyof D]: [P, D[P]] }[keyof
 export function entries<D extends object>(dict: D): ObjectEntry<D>[] {
   return Object.entries(dict) as ObjectEntry<D>[];
 }
+
+export function mapObject<T extends object, Out>(
+  object: T,
+  mapper: (value: T[keyof T], key: keyof T) => Out | undefined
+): { [P in keyof T]: Out } {
+  let out = dict() as Record<string, Out>;
+
+  Object.entries(object).forEach(([k, v]) => {
+    const value = mapper(v, k as keyof T);
+    if (value !== undefined) {
+      out[k] = value;
+    }
+  });
+
+  return out as { [P in keyof T]: Out };
+}