limu/lib/core/freeze.js

A fast js lib of immutable data, based on shallow copy on read and mark modified on write mechanism

import { isMap, isPrimitive, isSet, noop } from '../support/util';
export function deepFreeze(obj) {
    if (isPrimitive(obj)) {
        return obj;
    }
    // @ts-ignore
    if (Array.isArray(obj) && obj.length > 0) {
        obj.forEach(deepFreeze);
        return Object.freeze(obj);
    }
    if (isSet(obj)) {
        const set = obj;
        // TODO: throw error 'do not mutate' ?
        set.add = () => set;
        set.delete = () => false;
        set.clear = noop;
        // @ts-ignore
        for (const item of set.values()) {
            Object.freeze(item);
        }
        return Object.freeze(obj);
    }
    if (isMap(obj)) {
        const map = obj;
        // TODO: throw error 'do not mutate' ?
        map.set = () => map;
        map.delete = () => false;
        map.clear = noop;
        // @ts-ignore
        for (const item of map.values()) {
            Object.freeze(item);
        }
        return Object.freeze(obj);
    }
    // get all properties
    const propertyNames = Object.getOwnPropertyNames(obj);
    propertyNames.forEach((name) => {
        const value = obj[name];
        deepFreeze(value);
    });
    return Object.freeze(obj);
}