@mui/utils/esm/deepmerge/deepmerge.js

Utility functions for React components.

import * as React from 'react';
import { isValidElementType } from 'react-is';

// https://github.com/sindresorhus/is-plain-obj/blob/main/index.js
export function isPlainObject(item) {
  if (typeof item !== 'object' || item === null) {
    return false;
  }
  const prototype = Object.getPrototypeOf(item);
  return (prototype === null || prototype === Object.prototype || Object.getPrototypeOf(prototype) === null) && !(Symbol.toStringTag in item) && !(Symbol.iterator in item);
}
function deepClone(source) {
  if (/*#__PURE__*/React.isValidElement(source) || isValidElementType(source) || !isPlainObject(source)) {
    return source;
  }
  const output = {};
  Object.keys(source).forEach(key => {
    output[key] = deepClone(source[key]);
  });
  return output;
}

/**
 * Merge objects deeply.
 * It will shallow copy React elements.
 *
 * If `options.clone` is set to `false` the source object will be merged directly into the target object.
 *
 * @example
 * ```ts
 * deepmerge({ a: { b: 1 }, d: 2 }, { a: { c: 2 }, d: 4 });
 * // => { a: { b: 1, c: 2 }, d: 4 }
 * ````
 *
 * @param target The target object.
 * @param source The source object.
 * @param options The merge options.
 * @param options.clone Set to `false` to merge the source object directly into the target object.
 * @returns The merged object.
 */
export default function deepmerge(target, source, options = {
  clone: true
}) {
  const output = options.clone ? {
    ...target
  } : target;
  if (isPlainObject(target) && isPlainObject(source)) {
    Object.keys(source).forEach(key => {
      if (/*#__PURE__*/React.isValidElement(source[key]) || isValidElementType(source[key])) {
        output[key] = source[key];
      } else if (isPlainObject(source[key]) &&
      // Avoid prototype pollution
      Object.prototype.hasOwnProperty.call(target, key) && isPlainObject(target[key])) {
        // Since `output` is a clone of `target` and we have narrowed `target` in this block we can cast to the same type.
        output[key] = deepmerge(target[key], source[key], options);
      } else if (options.clone) {
        output[key] = isPlainObject(source[key]) ? deepClone(source[key]) : source[key];
      } else {
        output[key] = source[key];
      }
    });
  }
  return output;
}