132 lines
3.6 KiB
TypeScript
132 lines
3.6 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 {ɵstringify as stringify} from '@angular/core';
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import {MetadataOverride} from './metadata_override';
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type StringMap = {
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[key: string]: any
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};
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let _nextReferenceId = 0;
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export class MetadataOverrider {
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private _references = new Map<any, string>();
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/**
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* Creates a new instance for the given metadata class
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* based on an old instance and overrides.
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*/
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overrideMetadata<C extends T, T>(
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metadataClass: {new (options: T): C;}, oldMetadata: C, override: MetadataOverride<T>): C {
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const props: StringMap = {};
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if (oldMetadata) {
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_valueProps(oldMetadata).forEach((prop) => props[prop] = (<any>oldMetadata)[prop]);
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}
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if (override.set) {
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if (override.remove || override.add) {
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throw new Error(`Cannot set and add/remove ${stringify(metadataClass)} at the same time!`);
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}
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setMetadata(props, override.set);
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}
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if (override.remove) {
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removeMetadata(props, override.remove, this._references);
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}
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if (override.add) {
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addMetadata(props, override.add);
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}
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return new metadataClass(<any>props);
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}
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}
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function removeMetadata(metadata: StringMap, remove: any, references: Map<any, string>) {
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const removeObjects = new Set<string>();
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for (const prop in remove) {
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const removeValue = remove[prop];
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if (removeValue instanceof Array) {
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removeValue.forEach(
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(value: any) => { removeObjects.add(_propHashKey(prop, value, references)); });
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} else {
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removeObjects.add(_propHashKey(prop, removeValue, references));
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}
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}
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for (const prop in metadata) {
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const propValue = metadata[prop];
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if (propValue instanceof Array) {
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metadata[prop] = propValue.filter(
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(value: any) => !removeObjects.has(_propHashKey(prop, value, references)));
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} else {
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if (removeObjects.has(_propHashKey(prop, propValue, references))) {
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metadata[prop] = undefined;
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}
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}
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}
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}
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function addMetadata(metadata: StringMap, add: any) {
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for (const prop in add) {
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const addValue = add[prop];
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const propValue = metadata[prop];
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if (propValue != null && propValue instanceof Array) {
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metadata[prop] = propValue.concat(addValue);
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} else {
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metadata[prop] = addValue;
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}
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}
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}
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function setMetadata(metadata: StringMap, set: any) {
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for (const prop in set) {
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metadata[prop] = set[prop];
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}
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}
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function _propHashKey(propName: any, propValue: any, references: Map<any, string>): string {
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const replacer = (key: any, value: any) => {
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if (typeof value === 'function') {
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value = _serializeReference(value, references);
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}
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return value;
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};
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return `${propName}:${JSON.stringify(propValue, replacer)}`;
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}
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function _serializeReference(ref: any, references: Map<any, string>): string {
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let id = references.get(ref);
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if (!id) {
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id = `${stringify(ref)}${_nextReferenceId++}`;
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references.set(ref, id);
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}
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return id;
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}
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function _valueProps(obj: any): string[] {
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const props: string[] = [];
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// regular public props
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Object.keys(obj).forEach((prop) => {
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if (!prop.startsWith('_')) {
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props.push(prop);
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}
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});
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// getters
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let proto = obj;
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while (proto = Object.getPrototypeOf(proto)) {
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Object.keys(proto).forEach((protoProp) => {
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const desc = Object.getOwnPropertyDescriptor(proto, protoProp);
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if (!protoProp.startsWith('_') && desc && 'get' in desc) {
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props.push(protoProp);
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}
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});
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}
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return props;
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}
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