typescript-immutable-utils/es/objects.js

Type-safe immutability helpers for simple objects and arrays

export function update(target, values) {
    var hasChanged = false;
    for (var key in values) {
        if (!Object.prototype.hasOwnProperty.call(values, key))
            continue;
        if (values[key] !== target[key]) {
            hasChanged = true;
            break;
        }
    }
    return !hasChanged ? target : Object.assign({}, target, values);
}