@workday/canvas-kit-react/common/lib/theming/getObjectProxy.ts

The parent module that contains all Workday Canvas Kit React components

/**
 * For custom themes that do not overwrite every default.
 */
export type RecursivePartial<T> = {
  [P in keyof T]?: RecursivePartial<T[P]>;
};

/**
 * The functions gets a new object proxy. This is used for theme to ensure regardless of a partial theme object
 * there will be a fallback theme object so that properties aren't undefined regardless of the `target` object.
 * This function will also handle nested properties.
 * @param target A partial object with up to the same shape as the `fallback` object
 * @param fallback A fallback object. If a property to be accessed from the proxy is not available on the target object, the fallback object will be used
 */
export function getObjectProxy<T extends {}>(
  target: RecursivePartial<T> | undefined,
  fallback: T
): T {
  if (target) {
    return new Proxy(target, {
      get<T>(target: T, prop: string | symbol, receiver: any) {
        if (typeof (fallback as any)[prop] === 'object') {
          // @ts-ignore
          return getObjectProxy(target[prop], (fallback as any)[prop]);
        }
        const targetProp = target[prop as keyof T];
        if (targetProp !== undefined) {
          return targetProp;
        }
        return Reflect.get(fallback, prop, receiver);
      },
      ownKeys() {
        return Reflect.ownKeys(fallback);
      },
    }) as T;
  }
  return fallback;
}