nodejs fs读取静态json文件

let fs = require('fs'),
stream = fs.createReadStream('./obd.json'),
data = "";
stream.on('data',function(params){
    console.log(params);
    console.log(params.toString());
    data += params;
});
stream.on('end',function(){
    console.log(data);
    console.log(data.toString());
    console.log('finished!!!!');
});