将文本追加到现有的json文件node.js [英] Append text to existing json file node.js

问题描述

我正在尝试向现有的json文件中添加新文本，我尝试了writeFileSync和appendFileSync，但是即使我使用JSON.stringify，添加的文本也无法格式化为json.

I'm trying to add a new text to an existing json file, I tried writeFileSync and appendFileSync however the text added doesn't format as json even when i use JSON.stringify.

const fs = require('fs');

fs.readFile("test.json", (err, data) => {
  if( err) throw err;

  var data = JSON.parse(data);
  console.log(data);
});

var student = {
  age: "23"
};

fs.appendFileSync("test.json", "age: 23");
// var writeData = fs.writeFileSync("test.json", JSON.stringify(student));

我的json文件

{ name: "kevin" }

Append结果如下:{name:"kevin"} age:"23" 并且writeFileSync的结果类似于{name:"kevin"} {age:"23"}

Append turns out like this, {name: "kevin"}age: "23" and writeFileSync turns out like {name: "kevin"}{age: "23"}

我想要的是像这样连续向我的json文件中添加文本

What I want is to continuously add text to my json file like so

{
  name: "kevin",
  age: "23"
}

推荐答案

首先，不要使用readFileSync和writeFileSync.它们阻止执行，并违反了node.js标准.这是正确的代码:

First, dont use readFileSync and writeFileSync. They block the execution, and go against node.js standards. Here is the correct code:

const fs = require('fs');

fs.readFile("test.json", (err, data) => {  // READ
    if (err) {
        return console.error(err);
    };

    var data = JSON.parse(data.toString());
    data.age = "23"; // MODIFY
    var writeData = fs.writeFile("test.json", JSON.stringify(data), (err, result) => {  // WRITE
        if (err) {
            return console.error(err);
        } else {
            console.log(result);
            console.log("Success");
        }

    });
});

此代码的作用:

1. 从文件中读取数据.
2. 修改数据以获取文件应具有的新数据.
3. 将数据(不附加)写回到文件中.

1. Reads the data from the file.
2. Modifies the data to get the new data the file should have.
3. Write the data(NOT append) back to the file.

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