[Redux] Avoiding Object Mutations with Object.assign() and ...spread

最新推荐文章于 2025-09-01 15:51:00 发布

weixin_30672019

最新推荐文章于 2025-09-01 15:51:00 发布

阅读量61

点赞数

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/Answer1215/p/5006162.html

本文介绍如何利用Object.assign()方法及ES7中的扩展运算符来避免对象的直接修改，通过具体示例展示了如何使用这些特性来切换todo项的完成状态。

Learn how to use Object.assign() and the spread operator proposed for ES7 to avoid mutating objects.

/*
 * Open the console to see
 * that the tests have passed.
 */

const toggleTodo = (todo) => {
  return {
    ...todo,
    completed: !todo.completed
  };
};

const testToggleTodo = () => {
  const todoBefore = {
    id: 0,
    text: 'Learn Redux',
    completed: false
  };
  const todoAfter = {
    id: 0,
    text: 'Learn Redux',
    completed: true
  };
  
  deepFreeze(todoBefore);
  
  expect(
    toggleTodo(todoBefore)
  ).toEqual(todoAfter);
};

testToggleTodo();
console.log('All tests passed.');

Here '...todo', spread object, whcih is not available in ES6, but will be in ES7, It is fairly popular, and it is enabled in Babel if you use the stage two preset.

https://babeljs.io/docs/plugins/preset-stage-2/

转载于:https://www.cnblogs.com/Answer1215/p/5006162.html