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node：json与csv互转

原文：https://www.cnblogs.com/yhquan/p/10879836.html

【单个文件的转化】

1.安装json2csv模块将json转成csv

jsonToCSV.js

var fs = require('fs');
const Json2csvParser = require('json2csv').Parser;
const fields = ['car', 'price', 'color', 'for'];

let myData = fs.readFileSync('./data.json');
  
const json2csvParser = new Json2csvParser({ fields });

const csv = json2csvParser.parse(JSON.parse(myData));

fs.writeFile("./data.csv", csv, function(err) {
    if(err) {
        return console.log(err);
    }
    
    console.log("The file was saved!");
});

data.json

[
    {
      "car": "Audi",
      "price": 40000,
      "color": "blue",
      "for": ""
    }, {
      "car": "BMW",
      "price": 35000,
      "color": "black",
      "for": ""
    }, {
      "car": "Porsche",
      "price": 60000,
      "color": "green",
      "for": ""
    }
  ]

2.安装csvtojson模块将csv转成json

csvToJson.js

const csvFilePath = "./data.csv"
const csv=require('csvtojson');
var fs = require('fs');

csv()
.fromFile(csvFilePath)
.then((jsonObj)=>{
    jsonObj = JSON.stringify(jsonObj)
    fs.writeFile("./file/newData.json",jsonObj,'utf-8', function(err) {
        if(err) {
            return console.log(err);
        }
      
        console.log("The file was saved!");
    });
})

csv截图

优化：

【目录下多个文件转化】

文件目录截图

jsonToCSV.js

let fs = require('fs');
const curDirPath = 'F:/json2CSV/00originJson';
const Json2csvParser = require('json2csv').Parser;

fs.readdir(curDirPath, (err, files) => {
    if(err) {
        return console.log(err);
    }
    
    files.forEach(file => {
        
        fs.readFile(curDirPath + `/${file}`, 'utf-8', (err, data) => {
            if(err) {
                return console.log(err);
            }

            let keyArr = [];

            data = JSON.parse(data);

            for(let i in data) {
                keyArr.push(Object.keys(data[i]));
            }

            let keyArrSort = keyArr.sort((a, b) => {
                return b.length - a.length
            })

            let fields = keyArrSort[0];
  
            const json2csvParser = new Json2csvParser({ fields });

            const csv = json2csvParser.parse(data);
     
            let csvFileName = file.replace(/\.{1}[a-z]{1,}$/, ".csv");

            fs.writeFile(`./01csvFile/${csvFileName}`, csv, function(err) {
                if(err) {
                    return console.log(err);
                }
                
                console.log("The file was saved!");
            });

        });
    });
});

csvToJson.js

const curDirPath = 'F:/json2CSV/01csvFile';
const csv=require('csvtojson');
let fs = require('fs');

fs.readdir(curDirPath, (err, files) => {
    if(err) {
        return console.log(err);
    }
    
    files.forEach(fileName => {
        csv()
        .fromFile(`${curDirPath}/${fileName}`)
        .then((jsonObj)=>{

            jsonObj = JSON.stringify(jsonObj);

            let jsonFileName = fileName.replace(/\.{1}[a-z]{1,}$/, ".json");

            fs.writeFile(`./02newJsonFile/${jsonFileName}`, jsonObj, 'utf-8', function(err) {
                if(err) {
                    return console.log(err);
                }
            
                console.log("The file was saved!");
            });
        })
    });
});