perf: make metadata resolver a function

projects/ngx-meta/src/core/src/metadata-resolver.spec.ts

@@ -1,6 +1,5 @@
 import { TestBed } from '@angular/core/testing'
 
-import { MetadataResolver } from './metadata-resolver'
 import { MockProvider, MockProviders } from 'ng-mocks'
 import { enableAutoSpy } from '../../__tests__/enable-auto-spy'
 import { MetadataJsonResolver } from './metadata-json-resolver'
@@ -11,8 +10,13 @@ import { MaybeUndefined } from './maybe-undefined'
 import { Provider } from '@angular/core'
 import { DEFAULTS_TOKEN } from './defaults-token'
 import { makeMetadata } from './make-metadata'
+import {
+  METADATA_RESOLVER,
+  METADATA_RESOLVER_PROVIDER,
+  MetadataResolver,
+} from './metadata-resolver'
 
-describe('MetadataResolver', () => {
+describe('Metadata resolver', () => {
   enableAutoSpy()
 
   describe('get', () => {
@@ -51,7 +55,7 @@ describe('MetadataResolver', () => {
       })
 
       it('should resolve value using values', () => {
-        sut.get(dummyMetadata, dummyValues)
+        sut(dummyMetadata, dummyValues)
 
         expect(jsonResolver.get).toHaveBeenCalledWith(
           dummyMetadata,
@@ -60,7 +64,7 @@ describe('MetadataResolver', () => {
       })
 
       it('should return its value', () => {
-        expect(sut.get(dummyMetadata, dummyValues)).toEqual(value)
+        expect(sut(dummyMetadata, dummyValues)).toEqual(value)
       })
     })
 
@@ -73,7 +77,7 @@ describe('MetadataResolver', () => {
       })
 
       it('should resolve value using route metadata values', () => {
-        sut.get(dummyMetadata, dummyValues)
+        sut(dummyMetadata, dummyValues)
 
         expect(routeMetadataValues.get).toHaveBeenCalledOnceWith()
         expect(jsonResolver.get).toHaveBeenCalledWith(
@@ -83,7 +87,7 @@ describe('MetadataResolver', () => {
       })
 
       it('should return value obtained from route metadata values', () => {
-        expect(sut.get(dummyMetadata, dummyValues)).toEqual(value)
+        expect(sut(dummyMetadata, dummyValues)).toEqual(value)
       })
     })
 
@@ -96,13 +100,13 @@ describe('MetadataResolver', () => {
       })
 
       it('should resolve value using default values', () => {
-        sut.get(dummyMetadata, dummyValues)
+        sut(dummyMetadata, dummyValues)
 
         expect(jsonResolver.get).toHaveBeenCalledWith(dummyMetadata, defaults)
       })
 
       it('should return value obtained from defaults', () => {
-        expect(sut.get(dummyMetadata, dummyValues)).toEqual(value)
+        expect(sut(dummyMetadata, dummyValues)).toEqual(value)
       })
     })
 
@@ -126,7 +130,7 @@ describe('MetadataResolver', () => {
         })
 
         it('should return the merged object, with value props having more priority', () => {
-          expect(sut.get(dummyMetadata, dummyValues)).toEqual({
+          expect(sut(dummyMetadata, dummyValues)).toEqual({
             ...routeValueObject,
             ...valueObject,
           })
@@ -149,7 +153,7 @@ describe('MetadataResolver', () => {
         })
 
         it('should return value from values object', () => {
-          expect(sut.get(dummyMetadata, dummyValues)).toEqual(value)
+          expect(sut(dummyMetadata, dummyValues)).toEqual(value)
         })
       })
     })
@@ -160,15 +164,15 @@ describe('MetadataResolver', () => {
         injectSpies()
       })
       it('should return nothing', () => {
-        expect(sut.get(dummyMetadata, dummyValues)).toBeUndefined()
+        expect(sut(dummyMetadata, dummyValues)).toBeUndefined()
       })
     })
   })
 })
 
-function makeSut(opts: { defaults?: MetadataValues } = {}) {
+function makeSut(opts: { defaults?: MetadataValues } = {}): MetadataResolver {
   const providers: Provider[] = [
-    MetadataResolver,
+    METADATA_RESOLVER_PROVIDER,
     MockProviders(MetadataJsonResolver, RouteMetadataValues),
   ]
   if (opts.defaults) {
@@ -177,5 +181,5 @@ function makeSut(opts: { defaults?: MetadataValues } = {}) {
   TestBed.configureTestingModule({
     providers,
   })
-  return TestBed.inject(MetadataResolver)
+  return TestBed.inject(METADATA_RESOLVER)
 }

projects/ngx-meta/src/core/src/metadata-resolver.ts

@@ -1,4 +1,4 @@
-import { Inject, Injectable, Optional } from '@angular/core'
+import { FactoryProvider, InjectionToken, Optional } from '@angular/core'
 import { MetadataJsonResolver } from './metadata-json-resolver'
 import { MetadataValues } from './metadata-values'
 import { RouteMetadataValues } from './route-metadata-values'
@@ -7,28 +7,39 @@ import { isObject } from './is-object'
 import { Metadata } from './metadata'
 import { MaybeUndefined } from './maybe-undefined'
 
-@Injectable({ providedIn: 'root' })
-export class MetadataResolver {
-  constructor(
-    private readonly jsonResolver: MetadataJsonResolver,
-    private readonly routeMetadataValues: RouteMetadataValues,
-    @Optional()
-    @Inject(DEFAULTS_TOKEN)
-    private readonly defaults: MetadataValues | null,
-  ) {}
+export type MetadataResolver<T = unknown> = (
+  metadata: Metadata,
+  values: MetadataValues,
+) => T | undefined
+export const METADATA_RESOLVER = new InjectionToken<MetadataResolver>(
+  ngDevMode ? 'NgxMeta Metadata Resolver' : 'NgxMetaMR',
+)
 
-  get<T>(metadata: Metadata, values: MetadataValues): T | undefined {
-    const value = this.jsonResolver.get(metadata, values)
-    const routeValue = this.jsonResolver.get(
-      metadata,
-      this.routeMetadataValues.get(),
-    )
-    const defaultValue = this.jsonResolver.get(metadata, this.defaults ?? {})
+export const METADATA_RESOLVER_FACTORY: <T>(
+  ...deps: Exclude<FactoryProvider['deps'], undefined>
+) => MetadataResolver<T> =
+  (
+    jsonResolver: MetadataJsonResolver,
+    routeMetadataValues: RouteMetadataValues,
+    defaults: MetadataValues | null,
+  ) =>
+  <T>(metadata: Metadata, values: MetadataValues) => {
+    const value = jsonResolver.get(metadata, values)
+    const routeValue = jsonResolver.get(metadata, routeMetadataValues.get())
+    const defaultValue = jsonResolver.get(metadata, defaults ?? {})
     const effectiveValue =
       isObject(value) && (isObject(routeValue) || isObject(defaultValue))
         ? { ...(defaultValue as object), ...(routeValue as object), ...value }
         : [value, routeValue, defaultValue].find((v) => v !== undefined)
 
     return effectiveValue as MaybeUndefined<T>
   }
+export const METADATA_RESOLVER_PROVIDER: FactoryProvider = {
+  provide: METADATA_RESOLVER,
+  useFactory: METADATA_RESOLVER_FACTORY,
+  deps: [
+    MetadataJsonResolver,
+    RouteMetadataValues,
+    [DEFAULTS_TOKEN, new Optional()],
+  ],
 }

projects/ngx-meta/src/core/src/metadata.service.spec.ts

@@ -1,9 +1,9 @@
 import { TestBed } from '@angular/core/testing'
 import { MetadataService } from './metadata.service'
-import { MockProviders } from 'ng-mocks'
+import { MockProvider, MockProviders } from 'ng-mocks'
 import { makeMetadataProvider } from './__tests__/make-metadata-provider'
 import { enableAutoSpy } from '../../__tests__/enable-auto-spy'
-import { MetadataResolver } from './metadata-resolver'
+import { METADATA_RESOLVER, MetadataResolver } from './metadata-resolver'
 import { RouteMetadataValues } from './route-metadata-values'
 import { MetadataRegistry } from './metadata-registry'
 import { MaybeUndefined } from './maybe-undefined'
@@ -35,11 +35,11 @@ describe('MetadataService', () => {
 
     it('should set each metadata using resolved values', () => {
       const resolver = TestBed.inject(
-        MetadataResolver,
-      ) as unknown as jasmine.SpyObj<MetadataResolver>
+        METADATA_RESOLVER,
+      ) as unknown as jasmine.Spy<MetadataResolver>
       const dummyFirstMetadataValue = 'firstMetadataValue'
       const dummySecondMetadataValue = 'secondMetadataValue'
-      resolver.get.and.callFake(<T>(definition: Metadata) => {
+      resolver.and.callFake(<T>(definition: Metadata) => {
         switch (definition) {
           case firstMetadataProvider.metadata:
             return dummyFirstMetadataValue as MaybeUndefined<T>
@@ -52,15 +52,15 @@ describe('MetadataService', () => {
       sut.set(dummyValues)
 
       expect(metadataRegistry.getAll).toHaveBeenCalledOnceWith()
-      expect(resolver.get).toHaveBeenCalledTimes(2)
-      expect(resolver.get).toHaveBeenCalledWith(
+      expect(resolver).toHaveBeenCalledTimes(2)
+      expect(resolver).toHaveBeenCalledWith(
         firstMetadataProvider.metadata,
         dummyValues,
       )
       expect(firstMetadataProvider.set).toHaveBeenCalledWith(
         dummyFirstMetadataValue,
       )
-      expect(resolver.get).toHaveBeenCalledWith(
+      expect(resolver).toHaveBeenCalledWith(
         secondMetadataProvider.metadata,
         dummyValues,
       )
@@ -85,7 +85,8 @@ function makeSut() {
   TestBed.configureTestingModule({
     providers: [
       MetadataService,
-      MockProviders(MetadataRegistry, MetadataResolver, RouteMetadataValues),
+      MockProviders(MetadataRegistry, RouteMetadataValues),
+      MockProvider(METADATA_RESOLVER, jasmine.createSpy('Metadata resolver')),
     ],
   })
   return TestBed.inject(MetadataService)

projects/ngx-meta/src/core/src/metadata.service.ts

@@ -1,21 +1,21 @@
-import { Injectable } from '@angular/core'
-import { MetadataResolver } from './metadata-resolver'
+import { Inject, Injectable } from '@angular/core'
 import { MetadataValues } from './metadata-values'
 import { RouteMetadataValues } from './route-metadata-values'
 import { MetadataRegistry } from './metadata-registry'
+import { METADATA_RESOLVER, MetadataResolver } from './metadata-resolver'
 
 @Injectable({ providedIn: 'root' })
 export class MetadataService {
   constructor(
     private readonly registry: MetadataRegistry,
-    private readonly resolver: MetadataResolver,
+    @Inject(METADATA_RESOLVER) private readonly resolver: MetadataResolver,
     private readonly routeValues: RouteMetadataValues,
   ) {}
 
   public set(values: MetadataValues = {}): void {
     const allMetadata = this.registry.getAll()
     for (const metadata of allMetadata) {
-      metadata.set(this.resolver.get(metadata.metadata, values))
+      metadata.set(this.resolver(metadata.metadata, values))
     }
     this.routeValues.set(values)
   }

projects/ngx-meta/src/core/src/provide-core.ts

@@ -6,8 +6,12 @@ import {
 import { MetadataValues } from './metadata-values'
 import { DEFAULTS_TOKEN } from './defaults-token'
 import { HEAD_ELEMENT_UPSERT_OR_REMOVE_PROVIDER } from './head-element-upsert-or-remove'
+import { METADATA_RESOLVER_PROVIDER } from './metadata-resolver'
 
-export const CORE_PROVIDERS = [HEAD_ELEMENT_UPSERT_OR_REMOVE_PROVIDER]
+export const CORE_PROVIDERS = [
+  HEAD_ELEMENT_UPSERT_OR_REMOVE_PROVIDER,
+  METADATA_RESOLVER_PROVIDER,
+]
 
 export function provideCore(
   ...features: ReadonlyArray<CoreFeature>