如何在本地存储中存储对象数组? [英] How to store an array of objects in Local Storage?

问题描述

这是我的代码.几天以来，我一直在尝试创建一个对象数组，然后将其存储在本地存储中.问题来了，我需要先从本地存储中获取现有值.

This is my code. I am trying since a couple of days to create an Array of Objects, which I will then store in Local Storage. Here is the problem, I need to first Get the existing value from Local Storage.

然后我需要将新数据对象添加到现有数组中.然后我将其转换为 JSON，以便将其存储回本地存储.

I then need to add the new data object to the existing array. I then convert it into JSON so that I can store it back in the local storage.

onRegisterSubmit(){
    const user = {
        a: this.a,
        b: this.b,
        c: this.c,
      id: Date.now()
    }    

   var abc = [];
   var get =  JSON.parse(localStorage.getItem('user'));
   abc = [get];
   abc.push(user);

   localStorage.setItem('user', JSON.stringify(abc));

   console.log(JSON.stringify(abc));
   console.log(get);
  }

我希望 JSON 是一个像这样的对象数组，

I want the JSON to be an array of objects like this,

[{"hour":1,"minute":21,"ampm":"PM","repeatDays":[],"message":"","todayOrTomorrow":"Tomorrow","isRepeatMode":false,"isEnabled":false,"id":"1493797882440"},{"hour":1,"minute":24,"ampm":"PM","repeatDays":[],"message":"","todayOrTomorrow":"Tomorrow","isRepeatMode":false,"isEnabled":false,"id":"1493797896257"},{"hour":6,"minute":14,"ampm":"PM","repeatDays":[],"message":"","todayOrTomorrow":"Tomorrow","isRepeatMode":false,"isEnabled":false,"id":"1493815470408"}]

这是我的 JSON.

[[[[[[[{"id":1493820594019},{"id":1493820606448}],{"id":1493820609111}],{"id":1493820610150}],{"id":1493820610553}],{"id":1493820610827}],{"id":1493820611015}],{"id":1493820612018}]

我已经尝试了几天，任何帮助将不胜感激.

I've been trying for several days and any help will be greatly appreciated.

推荐答案

该代码的问题是:

1. 您将得到的结果包装在一个数组中，但理论上，您希望已经拥有一个数组.

您存储的是 user，而不是 get 或 abc. (您通过编辑删除了它.)

要存储数组，请执行以下操作:

To store the array, do what you're doing:

localStorage.setItem("users", JSON.stringify(users));

获取数组:

users = JSON.parse(localStorage.getItem("users") || "[]");

请注意，如果 getItem 返回 null，它会如何提供默认值(空数组)，因为我们从未将用户存储在那里.

Note how that provides a default (empty array) if getItem returns null because we've never stored our users there.

将用户添加到数组:

users.push({id: 1, foo: "bar"});

<小时>

示例(在 jsFiddle 上直播 [Stack Snippets 不允许本地存储]):

(function() { // Scoping function to avoid creating globals
    // Loading
    var users = JSON.parse(localStorage.getItem("users") || "[]");
    console.log("# of users: " + users.length);
    users.forEach(function(user, index) {
        console.log("[" + index + "]: " + user.id);
    });

    // Modifying
    var user = {
        id: Math.floor(Math.random() * 1000000)
    };
    users.push(user);
    console.log("Added user #" + user.id);

    // Saving
    localStorage.setItem("users", JSON.stringify(users));
})();

这会在控制台中显示当前用户的列表，每次刷新页面时都会添加一个.

That shows you the list of current users in the console, adding one each time you refresh the page.

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