JavaScript在对象中创建数组并将数据推送到数组 [英] JavaScript Creating array in object and push data to the array

问题描述

我是编程新手.我正在尝试React并具有addComment函数，该函数在用户向新闻添加评论时执行.此刻我需要创建一个属性 comments (数组)并将其分配或推送到该数组 inputCommentValue 值.但是现在我只重写数组的0元素，并且不能添加新元素.您能告诉我在哪里放置推送方法吗?谢谢！

I'm new to programming. I'm trying React and have function addComment which is executed when a user adds a comment to news.I need to create in this moment a property comments (array) and assign or push to this array inputCommentValue value. But right now I only rewrite 0 element of the array and can't add a new element. Can you please tell me where to put push method? Thank you!

var ARTICLES = [{
  title: "sit amet erat",
  text: "nam dui proin leo odio porttitor id consequat in consequat ut nulla sed accumsan"

}, {
  title: "pulvinar sed",
  text: "velit id pretium iaculis diam erat fermentum justo nec condimentum"
}]



addComment(index, inputCommentValue){
ARTICLES = [...ARTICLES], ARTICLES[index].comments=[inputCommentValue];
this.setState({ARTICLES:ARTICLES});
}

推荐答案

假定数据以组件的状态存在，则处理程序将看起来像这样

assuming that data exist in component's state , then handler will look something like that

addComment(index, inputCommentValue){
    // copy array , for not mutate state
    let ARTICLES = [...this.state.ARTICLES];
    // check if comments not exist
    if(!ARTICLES[index].comments) ARTICLES[index].comments=[];
    // add new comment to array
    ARTICLES[index].comments.push(inputCommentValue);
    // update component with new articles
    this.setState({ARTICLES:ARTICLES});
}

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