angular-docs-cn/packages/core/src/render3/interfaces/definition.ts

/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {SchemaMetadata, ViewEncapsulation} from '../../core';
import {ProcessProvidersFunction} from '../../di/interface/provider';
import {Type} from '../../interface/type';
import {CssSelectorList} from './projection';
import {TView} from './view';


/**
 * Definition of what a template rendering function should look like for a component.
 */
export type ComponentTemplate<T> = {
  // Note: the ctx parameter is typed as T|U, as using only U would prevent a template with
  // e.g. ctx: {} from being assigned to ComponentTemplate<any> as TypeScript won't infer U = any
  // in that scenario. By including T this incompatibility is resolved.
  <U extends T>(rf: RenderFlags, ctx: T | U): void;
};

/**
 * Definition of what a view queries function should look like.
 */
export type ViewQueriesFunction<T> = <U extends T>(rf: RenderFlags, ctx: U) => void;

/**
 * Definition of what a content queries function should look like.
 */
export type ContentQueriesFunction<T> =
    <U extends T>(rf: RenderFlags, ctx: U, directiveIndex: number) => void;

/**
 * Definition of what a factory function should look like.
 */
export type FactoryFn<T> = {
  /**
   * Subclasses without an explicit constructor call through to the factory of their base
   * definition, providing it with their own constructor to instantiate.
   */
  <U extends T>(t: Type<U>): U;

  /**
   * If no constructor to instantiate is provided, an instance of type T itself is created.
   */
  (t?: undefined): T;
};

/**
 * Flags passed into template functions to determine which blocks (i.e. creation, update)
 * should be executed.
 *
 * Typically, a template runs both the creation block and the update block on initialization and
 * subsequent runs only execute the update block. However, dynamically created views require that
 * the creation block be executed separately from the update block (for backwards compat).
 */
export const enum RenderFlags {
  /* Whether to run the creation block (e.g. create elements and directives) */
  Create = 0b01,

  /* Whether to run the update block (e.g. refresh bindings) */
  Update = 0b10
}

/**
 * A subclass of `Type` which has a static `ngComponentDef`:`ComponentDef` field making it
 * consumable for rendering.
 */
export interface ComponentType<T> extends Type<T> { ngComponentDef: never; }

/**
 * A subclass of `Type` which has a static `ngDirectiveDef`:`DirectiveDef` field making it
 * consumable for rendering.
 */
export interface DirectiveType<T> extends Type<T> {
  ngDirectiveDef: never;
  ngFactoryDef: () => T;
}

export const enum DirectiveDefFlags {ContentQuery = 0b10}

/**
 * A subclass of `Type` which has a static `ngPipeDef`:`PipeDef` field making it
 * consumable for rendering.
 */
export interface PipeType<T> extends Type<T> { ngPipeDef: never; }

/**
 * @codeGenApi
 */
export type ɵɵDirectiveDefWithMeta<
    T, Selector extends string, ExportAs extends string[], InputMap extends{[key: string]: string},
    OutputMap extends{[key: string]: string}, QueryFields extends string[]> = DirectiveDef<T>;

/**
 * Runtime information for classes that are inherited by components or directives
 * that aren't defined as components or directives.
 *
 * This is an internal data structure used by the renderer to determine what inputs
 * and outputs should be inherited.
 *
 * See: {@link defineBase}
 *
 * @codeGenApi
 */
export interface ɵɵBaseDef<T> {
  /**
   * A dictionary mapping the inputs' minified property names to their public API names, which
   * are their aliases if any, or their original unminified property names
   * (as in `@Input('alias') propertyName: any;`).
   */
  readonly inputs: {[P in keyof T]: string};

  /**
   * @deprecated This is only here because `NgOnChanges` incorrectly uses declared name instead of
   * public or minified name.
   */
  readonly declaredInputs: {[P in keyof T]: string};

  /**
   * A dictionary mapping the outputs' minified property names to their public API names, which
   * are their aliases if any, or their original unminified property names
   * (as in `@Output('alias') propertyName: any;`).
   */
  readonly outputs: {[P in keyof T]: string};

  /**
   * Function to create and refresh content queries associated with a given directive.
   */
  contentQueries: ContentQueriesFunction<T>|null;

  /**
   * Query-related instructions for a directive. Note that while directives don't have a
   * view and as such view queries won't necessarily do anything, there might be
   * components that extend the directive.
   */
  viewQuery: ViewQueriesFunction<T>|null;

  /**
   * Refreshes host bindings on the associated directive.
   */
  hostBindings: HostBindingsFunction<T>|null;
}

/**
 * Runtime link information for Directives.
 *
 * This is internal data structure used by the render to link
 * directives into templates.
 *
 * NOTE: Always use `defineDirective` function to create this object,
 * never create the object directly since the shape of this object
 * can change between versions.
 *
 * @param Selector type metadata specifying the selector of the directive or component
 *
 * See: {@link defineDirective}
 */
export interface DirectiveDef<T> extends ɵɵBaseDef<T> {
  /** Token representing the directive. Used by DI. */
  type: Type<T>;

  /** Function that resolves providers and publishes them into the DI system. */
  providersResolver:
      (<U extends T>(def: DirectiveDef<U>, processProvidersFn?: ProcessProvidersFunction) =>
           void)|null;

  /** The selectors that will be used to match nodes to this directive. */
  readonly selectors: CssSelectorList;

  /**
   * Name under which the directive is exported (for use with local references in template)
   */
  readonly exportAs: string[]|null;

  /**
   * Factory function used to create a new directive instance. Will be null initially.
   * Populated when the factory is first requested by directive instantiation logic.
   */
  factory: FactoryFn<T>|null;

  /* The following are lifecycle hooks for this component */
  onChanges: (() => void)|null;
  onInit: (() => void)|null;
  doCheck: (() => void)|null;
  afterContentInit: (() => void)|null;
  afterContentChecked: (() => void)|null;
  afterViewInit: (() => void)|null;
  afterViewChecked: (() => void)|null;
  onDestroy: (() => void)|null;

  /**
   * The features applied to this directive
   */
  readonly features: DirectiveDefFeature[]|null;

  setInput:
      (<U extends T>(
           this: DirectiveDef<U>, instance: U, value: any, publicName: string,
           privateName: string) => void)|null;
}

/**
 * @codeGenApi
 */
export type ɵɵComponentDefWithMeta<
    T, Selector extends String, ExportAs extends string[], InputMap extends{[key: string]: string},
    OutputMap extends{[key: string]: string}, QueryFields extends string[]> = ComponentDef<T>;

/**
 * @codeGenApi
 */
export type ɵɵFactoryDef<T> = () => T;

/**
 * Runtime link information for Components.
 *
 * This is internal data structure used by the render to link
 * components into templates.
 *
 * NOTE: Always use `defineComponent` function to create this object,
 * never create the object directly since the shape of this object
 * can change between versions.
 *
 * See: {@link defineComponent}
 */
export interface ComponentDef<T> extends DirectiveDef<T> {
  /**
   * Runtime unique component ID.
   */
  readonly id: string;

  /**
   * The View template of the component.
   */
  readonly template: ComponentTemplate<T>;

  /**
   * An array of `ngContent[selector]` values that were found in the template.
   */
  readonly ngContentSelectors?: string[];

  /**
   * A set of styles that the component needs to be present for component to render correctly.
   */
  readonly styles: string[];

  /**
   * The number of nodes, local refs, and pipes in this component template.
   *
   * Used to calculate the length of the component's LView array, so we
   * can pre-fill the array and set the binding start index.
   */
  // TODO(kara): remove queries from this count
  readonly consts: number;

  /**
   * The number of bindings in this component template (including pure fn bindings).
   *
   * Used to calculate the length of the component's LView array, so we
   * can pre-fill the array and set the host binding start index.
   */
  readonly vars: number;

  /**
   * Query-related instructions for a component.
   */
  viewQuery: ViewQueriesFunction<T>|null;

  /**
   * The view encapsulation type, which determines how styles are applied to
   * DOM elements. One of
   * - `Emulated` (default): Emulate native scoping of styles.
   * - `Native`: Use the native encapsulation mechanism of the renderer.
   * - `ShadowDom`: Use modern [ShadowDOM](https://w3c.github.io/webcomponents/spec/shadow/) and
   *   create a ShadowRoot for component's host element.
   * - `None`: Do not provide any template or style encapsulation.
   */
  readonly encapsulation: ViewEncapsulation;

  /**
   * Defines arbitrary developer-defined data to be stored on a renderer instance.
   * This is useful for renderers that delegate to other renderers.
   */
  readonly data: {[kind: string]: any};

  /** Whether or not this component's ChangeDetectionStrategy is OnPush */
  readonly onPush: boolean;

  /**
   * Registry of directives and components that may be found in this view.
   *
   * The property is either an array of `DirectiveDef`s or a function which returns the array of
   * `DirectiveDef`s. The function is necessary to be able to support forward declarations.
   */
  directiveDefs: DirectiveDefListOrFactory|null;

  /**
   * Registry of pipes that may be found in this view.
   *
   * The property is either an array of `PipeDefs`s or a function which returns the array of
   * `PipeDefs`s. The function is necessary to be able to support forward declarations.
   */
  pipeDefs: PipeDefListOrFactory|null;

  /**
   * The set of schemas that declare elements to be allowed in the component's template.
   */
  schemas: SchemaMetadata[]|null;

  /**
   * Ivy runtime uses this place to store the computed tView for the component. This gets filled on
   * the first run of component.
   */
  tView: TView|null;

  /**
   * Used to store the result of `noSideEffects` function so that it is not removed by closure
   * compiler. The property should never be read.
   */
  readonly _?: never;
}

/**
 * Runtime link information for Pipes.
 *
 * This is internal data structure used by the renderer to link
 * pipes into templates.
 *
 * NOTE: Always use `definePipe` function to create this object,
 * never create the object directly since the shape of this object
 * can change between versions.
 *
 * See: {@link definePipe}
 */
export interface PipeDef<T> {
  /** Token representing the pipe. */
  type: Type<T>;

  /**
   * Pipe name.
   *
   * Used to resolve pipe in templates.
   */
  readonly name: string;

  /**
   * Factory function used to create a new pipe instance. Will be null initially.
   * Populated when the factory is first requested by pipe instantiation logic.
   */
  factory: FactoryFn<T>|null;

  /**
   * Whether or not the pipe is pure.
   *
   * Pure pipes result only depends on the pipe input and not on internal
   * state of the pipe.
   */
  readonly pure: boolean;

  /* The following are lifecycle hooks for this pipe */
  onDestroy: (() => void)|null;
}

/**
 * @codeGenApi
 */
export type ɵɵPipeDefWithMeta<T, Name extends string> = PipeDef<T>;

export interface DirectiveDefFeature {
  <T>(directiveDef: DirectiveDef<T>): void;
  /**
   * Marks a feature as something that {@link InheritDefinitionFeature} will execute
   * during inheritance.
   *
   * NOTE: DO NOT SET IN ROOT OF MODULE! Doing so will result in tree-shakers/bundlers
   * identifying the change as a side effect, and the feature will be included in
   * every bundle.
   */
  ngInherit?: true;
}

export interface ComponentDefFeature {
  <T>(componentDef: ComponentDef<T>): void;
  /**
   * Marks a feature as something that {@link InheritDefinitionFeature} will execute
   * during inheritance.
   *
   * NOTE: DO NOT SET IN ROOT OF MODULE! Doing so will result in tree-shakers/bundlers
   * identifying the change as a side effect, and the feature will be included in
   * every bundle.
   */
  ngInherit?: true;
}


/**
 * Type used for directiveDefs on component definition.
 *
 * The function is necessary to be able to support forward declarations.
 */
export type DirectiveDefListOrFactory = (() => DirectiveDefList) | DirectiveDefList;

export type DirectiveDefList = (DirectiveDef<any>| ComponentDef<any>)[];

export type DirectiveTypesOrFactory = (() => DirectiveTypeList) | DirectiveTypeList;

export type DirectiveTypeList =
    (DirectiveType<any>| ComponentType<any>|
     Type<any>/* Type as workaround for: Microsoft/TypeScript/issues/4881 */)[];

export type HostBindingsFunction<T> =
    <U extends T>(rf: RenderFlags, ctx: U, elementIndex: number) => void;

/**
 * Type used for PipeDefs on component definition.
 *
 * The function is necessary to be able to support forward declarations.
 */
export type PipeDefListOrFactory = (() => PipeDefList) | PipeDefList;

export type PipeDefList = PipeDef<any>[];

export type PipeTypesOrFactory = (() => PipeTypeList) | PipeTypeList;

export type PipeTypeList =
    (PipeType<any>| Type<any>/* Type as workaround for: Microsoft/TypeScript/issues/4881 */)[];


// Note: This hack is necessary so we don't erroneously get a circular dependency
// failure based on types.
export const unusedValueExportToPlacateAjd = 1;