angular-cn/modules/@angular/compiler/testing/metadata_overrider.ts

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