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metadata_overrider.ts
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148 lines (132 loc) · 4.13 KB
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/**
* @license
* Copyright Google LLC 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.dev/license
*/
import {ɵstringify as stringify} from '@angular/core';
import {MetadataOverride} from './metadata_override';
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 ${stringify(metadataClass)} at the same time!`);
}
setMetadata(props, override.set);
}
if (override.remove) {
removeMetadata(props, override.remove, this._references);
}
if (override.add) {
addMetadata(props, override.add);
}
return new metadataClass(<any>props);
}
}
function removeMetadata(metadata: StringMap, remove: any, references: Map<any, string>) {
const removeObjects = new Set<string>();
for (const prop in remove) {
const removeValue = remove[prop];
if (Array.isArray(removeValue)) {
removeValue.forEach((value: any) => {
removeObjects.add(_propHashKey(prop, value, references));
});
} else {
removeObjects.add(_propHashKey(prop, removeValue, references));
}
}
for (const prop in metadata) {
const propValue = metadata[prop];
if (Array.isArray(propValue)) {
metadata[prop] = propValue.filter(
(value: any) => !removeObjects.has(_propHashKey(prop, value, references)),
);
} else {
if (removeObjects.has(_propHashKey(prop, propValue, references))) {
metadata[prop] = undefined;
}
}
}
}
function addMetadata(metadata: StringMap, add: any) {
for (const prop in add) {
const addValue = add[prop];
const propValue = metadata[prop];
if (propValue != null && Array.isArray(propValue)) {
metadata[prop] = propValue.concat(addValue);
} else {
metadata[prop] = addValue;
}
}
}
function setMetadata(metadata: StringMap, set: any) {
for (const prop in set) {
metadata[prop] = set[prop];
}
}
function _propHashKey(propName: any, propValue: any, references: Map<any, string>): string {
let nextObjectId = 0;
const objectIds = new Map<object, string>();
const replacer = (key: any, value: any) => {
if (value !== null && typeof value === 'object') {
if (objectIds.has(value)) {
return objectIds.get(value);
}
// Record an id for this object such that any later references use the object's id instead
// of the object itself, in order to break cyclic pointers in objects.
objectIds.set(value, `ɵobj#${nextObjectId++}`);
// The first time an object is seen the object itself is serialized.
return value;
} else 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) => {
const desc = Object.getOwnPropertyDescriptor(proto, protoProp);
if (!protoProp.startsWith('_') && desc && 'get' in desc) {
props.push(protoProp);
}
});
}
return props;
}