5be186035f
This commit creates an API for factory functions which allows them to be inherited from one another. To do so, it differentiates between the factory function as a wrapper for a constructor and the factory function in ngInjectableDefs which is determined by a default provider. The new form is: factory: (t?) => new (t || SomeType)(inject(Dep1), inject(Dep2)) The 't' parameter allows for constructor inheritance. A subclass with no declared constructor inherits its constructor from the superclass. With the 't' parameter, a subclass can call the superclass' factory function and use it to create an instance of the subclass. For @Injectables with configured providers, the factory function is of the form: factory: (t?) => t ? constructorInject(t) : provider(); where constructorInject(t) creates an instance of 't' using the naturally declared constructor of the type, and where provider() creates an instance of the base type using the special declared provider on @Injectable. PR Close #25392
112 lines
3.7 KiB
TypeScript
112 lines
3.7 KiB
TypeScript
/**
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* @license
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* Copyright Google Inc. All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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import {InjectFlags} from './core';
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import {Identifiers} from './identifiers';
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import * as o from './output/output_ast';
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import {R3DependencyMetadata, R3FactoryDelegateType, R3FactoryMetadata, compileFactoryFunction} from './render3/r3_factory';
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import {mapToMapExpression} from './render3/util';
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export interface InjectableDef {
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expression: o.Expression;
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type: o.Type;
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statements: o.Statement[];
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}
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export interface R3InjectableMetadata {
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name: string;
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type: o.Expression;
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ctorDeps: R3DependencyMetadata[]|null;
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providedIn: o.Expression;
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useClass?: o.Expression;
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useFactory?: o.Expression;
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useExisting?: o.Expression;
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useValue?: o.Expression;
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userDeps?: R3DependencyMetadata[];
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}
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export function compileInjectable(meta: R3InjectableMetadata): InjectableDef {
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let result: {factory: o.Expression, statements: o.Statement[]}|null = null;
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function makeFn(ret: o.Expression): o.Expression {
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return o.fn([], [new o.ReturnStatement(ret)], undefined, undefined, `${meta.name}_Factory`);
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}
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const factoryMeta = {
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name: meta.name,
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type: meta.type,
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deps: meta.ctorDeps,
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injectFn: Identifiers.inject,
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};
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if (meta.useClass !== undefined) {
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// meta.useClass has two modes of operation. Either deps are specified, in which case `new` is
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// used to instantiate the class with dependencies injected, or deps are not specified and
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// the factory of the class is used to instantiate it.
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//
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// A special case exists for useClass: Type where Type is the injectable type itself, in which
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// case omitting deps just uses the constructor dependencies instead.
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const useClassOnSelf = meta.useClass.isEquivalent(meta.type);
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const deps = meta.userDeps || (useClassOnSelf && meta.ctorDeps) || undefined;
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if (deps !== undefined) {
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// factory: () => new meta.useClass(...deps)
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result = compileFactoryFunction({
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...factoryMeta,
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delegate: meta.useClass,
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delegateDeps: deps,
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delegateType: R3FactoryDelegateType.Class,
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});
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} else {
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result = compileFactoryFunction({
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...factoryMeta,
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delegate: meta.useClass,
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delegateType: R3FactoryDelegateType.Factory,
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});
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}
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} else if (meta.useFactory !== undefined) {
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result = compileFactoryFunction({
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...factoryMeta,
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delegate: meta.useFactory,
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delegateDeps: meta.userDeps || [],
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delegateType: R3FactoryDelegateType.Function,
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});
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} else if (meta.useValue !== undefined) {
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// Note: it's safe to use `meta.useValue` instead of the `USE_VALUE in meta` check used for
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// client code because meta.useValue is an Expression which will be defined even if the actual
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// value is undefined.
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result = compileFactoryFunction({
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...factoryMeta,
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expression: meta.useValue,
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});
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} else if (meta.useExisting !== undefined) {
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// useExisting is an `inject` call on the existing token.
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result = compileFactoryFunction({
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...factoryMeta,
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expression: o.importExpr(Identifiers.inject).callFn([meta.useExisting]),
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});
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} else {
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result = compileFactoryFunction(factoryMeta);
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}
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const token = meta.type;
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const providedIn = meta.providedIn;
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const expression = o.importExpr(Identifiers.defineInjectable).callFn([mapToMapExpression(
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{token, factory: result.factory, providedIn})]);
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const type = new o.ExpressionType(
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o.importExpr(Identifiers.InjectableDef, [new o.ExpressionType(meta.type)]));
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return {
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expression,
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type,
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statements: result.statements,
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};
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}
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