keycloak_theme/src/tools/deepAssign.ts

import { assert } from "tsafe/assert";
import { is } from "tsafe/is";
import { deepClone } from "./deepClone";

//Warning: Be mindful that because of array this is not idempotent.
export function deepAssign(params: {
    target: Record<string, unknown>;
    source: Record<string, unknown>;
}) {
    const { target } = params;

    const source = deepClone(params.source);

    Object.keys(source).forEach(key => {
        var dereferencedSource = source[key];

        if (
            target[key] === undefined ||
            dereferencedSource instanceof Function ||
            !(dereferencedSource instanceof Object)
        ) {
            Object.defineProperty(target, key, {
                enumerable: true,
                writable: true,
                configurable: true,
                value: dereferencedSource
            });

            return;
        }

        const dereferencedTarget = target[key];

        if (dereferencedSource instanceof Array) {
            assert(is<unknown[]>(dereferencedTarget));
            assert(is<unknown[]>(dereferencedSource));

            dereferencedSource.forEach(entry => dereferencedTarget.push(entry));

            return;
        }

        assert(is<Record<string, unknown>>(dereferencedTarget));
        assert(is<Record<string, unknown>>(dereferencedSource));

        deepAssign({
            target: dereferencedTarget,
            source: dereferencedSource
        });
    });
}