From 1b977e96044c11bf897b22a92986d4ecdb65112b Mon Sep 17 00:00:00 2001
From: Alex Kanunnikov <lifeart92@gmail.com>
Date: Tue, 5 Dec 2023 12:37:29 +0300
Subject: [PATCH] [perf | size] simplify array iterations

---
 .../runtime/lib/compiled/expressions/concat.ts   | 16 ++++++++--------
 .../runtime/lib/compiled/opcodes/component.ts    |  7 +------
 .../@glimmer/runtime/lib/compiled/opcodes/dom.ts |  7 +++----
 packages/@glimmer/runtime/lib/scope.ts           | 12 ++----------
 4 files changed, 14 insertions(+), 28 deletions(-)

diff --git a/packages/@glimmer/runtime/lib/compiled/expressions/concat.ts b/packages/@glimmer/runtime/lib/compiled/expressions/concat.ts
index aa8b06ec5..6d50ba0e2 100644
--- a/packages/@glimmer/runtime/lib/compiled/expressions/concat.ts
+++ b/packages/@glimmer/runtime/lib/compiled/expressions/concat.ts
@@ -1,17 +1,15 @@
-import type { Dict, Maybe } from '@glimmer/interfaces';
 import type { Reference } from '@glimmer/reference';
 import { createComputeRef, valueForRef } from '@glimmer/reference';
-import { enumerate } from '@glimmer/util';
 
 export function createConcatRef(partsRefs: Reference[]) {
   return createComputeRef(() => {
-    let parts = new Array<string>();
+    const parts: string[] = [];
 
-    for (const [i, ref] of enumerate(partsRefs)) {
-      let value = valueForRef(ref) as Maybe<Dict>;
+    for (const ref of partsRefs) {
+      const value = valueForRef(ref);
 
       if (value !== null && value !== undefined) {
-        parts[i] = castToString(value);
+        parts.push(castToString(value));
       }
     }
 
@@ -23,8 +21,10 @@ export function createConcatRef(partsRefs: Reference[]) {
   });
 }
 
-function castToString(value: Dict) {
-  if (typeof value.toString !== 'function') {
+function castToString(value: string | object) {
+  if (typeof value === 'string') {
+    return value;
+  } else if (typeof value.toString !== 'function') {
     return '';
   }
 
diff --git a/packages/@glimmer/runtime/lib/compiled/opcodes/component.ts b/packages/@glimmer/runtime/lib/compiled/opcodes/component.ts
index 597e4cb01..36749bf03 100644
--- a/packages/@glimmer/runtime/lib/compiled/opcodes/component.ts
+++ b/packages/@glimmer/runtime/lib/compiled/opcodes/component.ts
@@ -534,12 +534,7 @@ function mergeClasses(classes: (string | Reference)[]): string | Reference<unkno
 }
 
 function allStringClasses(classes: (string | Reference<unknown>)[]): classes is string[] {
-  for (let i = 0; i < classes.length; i++) {
-    if (typeof classes[i] !== 'string') {
-      return false;
-    }
-  }
-  return true;
+  return classes.every((c) => typeof c === 'string');
 }
 
 function setDeferredAttr(
diff --git a/packages/@glimmer/runtime/lib/compiled/opcodes/dom.ts b/packages/@glimmer/runtime/lib/compiled/opcodes/dom.ts
index 1b60adaa4..74f94016f 100644
--- a/packages/@glimmer/runtime/lib/compiled/opcodes/dom.ts
+++ b/packages/@glimmer/runtime/lib/compiled/opcodes/dom.ts
@@ -91,13 +91,12 @@ APPEND_OPCODES.add(Op.FlushElement, (vm) => {
 APPEND_OPCODES.add(Op.CloseElement, (vm) => {
   let modifiers = vm.elements().closeElement();
 
-  if (modifiers) {
+  if (modifiers !== null) {
     modifiers.forEach((modifier) => {
       vm.env.scheduleInstallModifier(modifier);
-      let { manager, state } = modifier;
-      let d = manager.getDestroyable(state);
+      const d = modifier.manager.getDestroyable(modifier.state);
 
-      if (d) {
+      if (d !== null) {
         vm.associateDestroyable(d);
       }
     });
diff --git a/packages/@glimmer/runtime/lib/scope.ts b/packages/@glimmer/runtime/lib/scope.ts
index b470360bb..44226d4e8 100644
--- a/packages/@glimmer/runtime/lib/scope.ts
+++ b/packages/@glimmer/runtime/lib/scope.ts
@@ -43,21 +43,13 @@ export function isScopeReference(s: ScopeSlot): s is Reference {
 
 export class PartialScopeImpl implements PartialScope {
   static root(self: Reference<unknown>, size = 0, owner: Owner): PartialScope {
-    let refs: Reference<unknown>[] = new Array(size + 1);
-
-    for (let i = 0; i <= size; i++) {
-      refs[i] = UNDEFINED_REFERENCE;
-    }
+    let refs: Reference<unknown>[] = new Array(size + 1).fill(UNDEFINED_REFERENCE);
 
     return new PartialScopeImpl(refs, owner, null, null, null).init({ self });
   }
 
   static sized(size = 0, owner: Owner): Scope {
-    let refs: Reference<unknown>[] = new Array(size + 1);
-
-    for (let i = 0; i <= size; i++) {
-      refs[i] = UNDEFINED_REFERENCE;
-    }
+    let refs: Reference<unknown>[] = new Array(size + 1).fill(UNDEFINED_REFERENCE);
 
     return new PartialScopeImpl(refs, owner, null, null, null);
   }