@nestjs/config/dist/utils/merge-configs.util.js

Configuration for NestJS: load .env files and custom configuration, validate it at startup, and read it through an injectable ConfigService.

import { setProperty } from './property-path.util.js';
/**
 * @publicApi
 */
export function mergeConfigObject(host, partial, token) {
    if (token) {
        setProperty(host, token, partial);
        return partial;
    }
    Object.assign(host, partial);
}