fix(core): remove duplicated EMPTY_ARRAY constant (#40587)

cexbrayat · mhevery · commit abdf25c679dd · 2021-01-28T08:55:53.000-08:00
The codebase currently contains several `EMPTY_ARRAY` constants, and they can end up in the bundle of an application. A recent commit 6fbe219 tipped us off as it introduced several `noop` occurrences in the golden symbol files. After investigating with @petebacondarwin, we decided to remove the duplicated symbols. This probably shaves only a few bytes, but this commit removes the duplicated functions, by always using the one in `core/src/utils/empty`. PR Close #40587
diff --git a/packages/core/src/di/r3_injector.ts b/packages/core/src/di/r3_injector.ts
@@ -13,6 +13,7 @@ import {AbstractType, Type} from '../interface/type';
 import {FactoryFn, getFactoryDef} from '../render3/definition_factory';
 import {throwCyclicDependencyError, throwInvalidProviderError, throwMixedMultiProviderError} from '../render3/errors_di';
 import {deepForEach, newArray} from '../util/array_utils';
+import {EMPTY_ARRAY} from '../util/empty';
 import {stringify} from '../util/stringify';
 
 import {resolveForwardRef} from './forward_ref';
@@ -48,8 +49,6 @@ const NOT_YET = {};
  */
 const CIRCULAR = {};
 
-const EMPTY_ARRAY = [] as any[];
-
 /**
  * A lazily initialized NullInjector.
  */
diff --git a/packages/core/src/di/util.ts b/packages/core/src/di/util.ts
@@ -8,6 +8,7 @@
 
 import {Type} from '../interface/type';
 import {ReflectionCapabilities} from '../reflection/reflection_capabilities';
+import {EMPTY_ARRAY} from '../util/empty';
 import {getClosureSafeProperty} from '../util/property';
 
 import {resolveForwardRef} from './forward_ref';
@@ -16,7 +17,6 @@ import {ClassSansProvider, ConstructorSansProvider, ExistingSansProvider, Factor
 
 const USE_VALUE =
     getClosureSafeProperty<ValueProvider>({provide: String, useValue: getClosureSafeProperty});
-const EMPTY_ARRAY: any[] = [];
 
 export function convertInjectableProviderToFactory(
     type: Type<any>,
diff --git a/packages/core/src/render3/context_discovery.ts b/packages/core/src/render3/context_discovery.ts
@@ -9,7 +9,7 @@ import '../util/ng_dev_mode';
 
 import {assertDomNode} from '../util/assert';
 
-import {EMPTY_ARRAY} from './empty';
+import {EMPTY_ARRAY} from '../util/empty';
 import {LContext, MONKEY_PATCH_KEY_NAME} from './interfaces/context';
 import {TNode, TNodeFlags} from './interfaces/node';
 import {RElement, RNode} from './interfaces/renderer_dom';
diff --git a/packages/core/src/render3/definition.ts b/packages/core/src/render3/definition.ts
@@ -12,9 +12,10 @@ import {NgModuleDef, NgModuleType} from '../metadata/ng_module_def';
 import {SchemaMetadata} from '../metadata/schema';
 import {ViewEncapsulation} from '../metadata/view';
 import {noSideEffects} from '../util/closure';
+import {EMPTY_ARRAY} from '../util/empty';
 import {initNgDevMode} from '../util/ng_dev_mode';
 import {stringify} from '../util/stringify';
-import {EMPTY_ARRAY, EMPTY_OBJ} from './empty';
+import {EMPTY_OBJ} from './empty';
 import {NG_COMP_DEF, NG_DIR_DEF, NG_LOC_ID_DEF, NG_MOD_DEF, NG_PIPE_DEF} from './fields';
 import {ComponentDef, ComponentDefFeature, ComponentTemplate, ComponentType, ContentQueriesFunction, DirectiveDef, DirectiveDefFeature, DirectiveTypesOrFactory, HostBindingsFunction, PipeDef, PipeTypesOrFactory, ViewQueriesFunction} from './interfaces/definition';
 import {AttributeMarker, TAttributes, TConstantsOrFactory} from './interfaces/node';
diff --git a/packages/core/src/render3/empty.ts b/packages/core/src/render3/empty.ts
@@ -15,14 +15,11 @@ import {initNgDevMode} from '../util/ng_dev_mode';
  */
 
 export const EMPTY_OBJ: {} = {};
-export const EMPTY_ARRAY: any[] = [];
 
 // freezing the values prevents any code from accidentally inserting new values in
 if ((typeof ngDevMode === 'undefined' || ngDevMode) && initNgDevMode()) {
   // These property accesses can be ignored because ngDevMode will be set to false
   // when optimizing code and the whole if statement will be dropped.
   // tslint:disable-next-line:no-toplevel-property-access
   Object.freeze(EMPTY_OBJ);
-  // tslint:disable-next-line:no-toplevel-property-access
-  Object.freeze(EMPTY_ARRAY);
 }
diff --git a/packages/core/src/render3/features/inherit_definition_feature.ts b/packages/core/src/render3/features/inherit_definition_feature.ts
@@ -7,8 +7,9 @@
  */
 
 import {Type, Writable} from '../../interface/type';
+import {EMPTY_ARRAY} from '../../util/empty';
 import {fillProperties} from '../../util/property';
-import {EMPTY_ARRAY, EMPTY_OBJ} from '../empty';
+import {EMPTY_OBJ} from '../empty';
 import {ComponentDef, ContentQueriesFunction, DirectiveDef, DirectiveDefFeature, HostBindingsFunction, RenderFlags, ViewQueriesFunction} from '../interfaces/definition';
 import {TAttributes} from '../interfaces/node';
 import {isComponentDef} from '../interfaces/type_checks';
diff --git a/packages/core/src/render3/instructions/i18n_icu_container_visitor.ts b/packages/core/src/render3/instructions/i18n_icu_container_visitor.ts
@@ -7,8 +7,8 @@
  */
 
 import {assertDomNode, assertNumber, assertNumberInRange} from '../../util/assert';
+import {EMPTY_ARRAY} from '../../util/empty';
 import {assertTIcu, assertTNodeForLView} from '../assert';
-import {EMPTY_ARRAY} from '../empty';
 import {getCurrentICUCaseIndex} from '../i18n/i18n_util';
 import {I18nRemoveOpCodes, TIcu} from '../interfaces/i18n';
 import {TIcuContainerNode} from '../interfaces/node';
diff --git a/packages/core/src/render3/jit/directive.ts b/packages/core/src/render3/jit/directive.ts
@@ -15,9 +15,10 @@ import {Query} from '../../metadata/di';
 import {Component, Directive, Input} from '../../metadata/directives';
 import {componentNeedsResolution, maybeQueueResolutionOfComponentResources} from '../../metadata/resource_loading';
 import {ViewEncapsulation} from '../../metadata/view';
+import {EMPTY_ARRAY} from '../../util/empty';
 import {initNgDevMode} from '../../util/ng_dev_mode';
 import {getComponentDef, getDirectiveDef} from '../definition';
-import {EMPTY_ARRAY, EMPTY_OBJ} from '../empty';
+import {EMPTY_OBJ} from '../empty';
 import {NG_COMP_DEF, NG_DIR_DEF, NG_FACTORY_DEF} from '../fields';
 import {ComponentType} from '../interfaces/definition';
 import {stringifyForError} from '../util/stringify_utils';
diff --git a/packages/core/src/render3/jit/module.ts b/packages/core/src/render3/jit/module.ts
@@ -16,6 +16,7 @@ import {ModuleWithProviders, NgModule} from '../../metadata/ng_module';
 import {NgModuleDef, NgModuleTransitiveScopes, NgModuleType} from '../../metadata/ng_module_def';
 import {deepForEach, flatten} from '../../util/array_utils';
 import {assertDefined} from '../../util/assert';
+import {EMPTY_ARRAY} from '../../util/empty';
 import {getComponentDef, getDirectiveDef, getNgModuleDef, getPipeDef} from '../definition';
 import {NG_COMP_DEF, NG_DIR_DEF, NG_MOD_DEF, NG_PIPE_DEF} from '../fields';
 import {ComponentDef} from '../interfaces/definition';
@@ -24,8 +25,6 @@ import {stringifyForError} from '../util/stringify_utils';
 
 import {angularCoreEnv} from './environment';
 
-const EMPTY_ARRAY: Type<any>[] = [];
-
 interface ModuleQueueItem {
   moduleType: Type<any>;
   ngModule: NgModule;
diff --git a/packages/core/src/view/index.ts b/packages/core/src/view/index.ts
@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+export {EMPTY_ARRAY} from '../util/empty';
 export {anchorDef, elementDef} from './element';
 export {clearOverrides, createNgModuleFactory, overrideComponentView, overrideProvider} from './entrypoint';
 export {ngContentDef} from './ng_content';
@@ -16,7 +17,7 @@ export {queryDef} from './query';
 export {createComponentFactory, getComponentViewDefinitionFactory, nodeValue, ViewRef_} from './refs';
 export {initServicesIfNeeded} from './services';
 export {textDef} from './text';
-export {createRendererType2, elementEventFullName, EMPTY_ARRAY, EMPTY_MAP, inlineInterpolate, interpolate, rootRenderNodes, tokenKey, unwrapValue} from './util';
+export {createRendererType2, elementEventFullName, EMPTY_MAP, inlineInterpolate, interpolate, rootRenderNodes, tokenKey, unwrapValue} from './util';
 export {viewDef} from './view';
 export {attachEmbeddedView, detachEmbeddedView, moveEmbeddedView} from './view_attach';
 
diff --git a/packages/core/src/view/util.ts b/packages/core/src/view/util.ts
@@ -444,5 +444,4 @@ function _toStringWithNull(v: any): string {
   return v != null ? v.toString() : '';
 }
 
-export const EMPTY_ARRAY: any[] = [];
 export const EMPTY_MAP: {[key: string]: any} = {};
diff --git a/packages/core/test/bundling/forms/bundle.golden_symbols.json b/packages/core/test/bundling/forms/bundle.golden_symbols.json
@@ -173,12 +173,6 @@
   {
     "name": "EMPTY_ARRAY"
   },
-  {
-    "name": "EMPTY_ARRAY"
-  },
-  {
-    "name": "EMPTY_ARRAY"
-  },
   {
     "name": "EMPTY_OBJ"
   },
diff --git a/packages/core/test/bundling/router/bundle.golden_symbols.json b/packages/core/test/bundling/router/bundle.golden_symbols.json
@@ -236,9 +236,6 @@
   {
     "name": "EMPTY_ARRAY"
   },
-  {
-    "name": "EMPTY_ARRAY"
-  },
   {
     "name": "EMPTY_OBJ"
   },
diff --git a/packages/core/test/bundling/todo/bundle.golden_symbols.json b/packages/core/test/bundling/todo/bundle.golden_symbols.json
@@ -14,9 +14,6 @@
   {
     "name": "EMPTY_ARRAY"
   },
-  {
-    "name": "EMPTY_ARRAY"
-  },
   {
     "name": "EMPTY_OBJ"
   },
