hand-made, lightweight utility functions to do value operations.

utils.ts

/**
 * test if the target is an object(array included)
 */
export function isObject(obj: any): boolean {
  return obj !== null && typeof obj === 'object';
}

/** simple deep equal */
export function isEqual(a: any, b: any): boolean {
  if (isObject(a) && isObject(b)) {
    const aKeys = Object.keys(a);
    const bKeys = Object.keys(b);
    if (aKeys.length !== bKeys.length) {
      return false;
    } else {
      return aKeys.every((key) => isEqual(a[key], b[key]));
    }
  } else {
    return a === b;
  }
}

/** simple deep merge */
export function merge<T>(val: T, data: any): T {
  let merged: any = val;
  if (isObject(val)) {
    // ignore simple val into object
    if (isObject(data)) {
      Object.keys(data).forEach((key, index) => {
        const src = (val as any)[key];
        const dst = data[key];
        (val as any)[key] = merge(src, dst);
      });
    }
  } else {
    //  if src is not object, just replace it
    merged = data;
  }
  return merged as T;
}

/** simple deep clone, without retain ref */
export function cloneDeep<T>(val: T): T {
  let cloned: any;
  if (Array.isArray(val)) {
    cloned = [];
    (val as any).forEach((item: any, idx: number) => {
      cloned[idx] = cloneDeep(item);
    });
  } else if (isObject(val)) {
    cloned = {};
    Object.keys(val).forEach((key) => {
      cloned[key] = cloneDeep((val as any)[key]);
    });
  } else {
    cloned = val;
  }

  return cloned as T;
}