for循环中的Javascript内存泄漏

Question

当我在 node.js 中运行以下代码时，我收到以下错误消息：

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory

//Running this code causes program to run out of memory.
for(var i = 0; i < files.length; i++){
        readFile(files[i]); 
}

//log each line of file to console
function readFile(data){
    var lines = fs.readFileSync(data).toString().split('\n');
    for(var k = 0; k < lines.length; k++){
        console.log(lines[k]);
    }
}

但是，如果我更改 readFile 函数并将 console.log(lines[k]) 从 for 循环中取出，致命错误就会消失。这是为什么？以及如何修复原始代码以使其不再耗尽内存？

function readFile(data){
    var lines = fs.readFileSync(data).toString().split('\n');
    var string = ''
    for(var k = 0; k < lines.length; k++){
        //console.log(lines[k]);
        string += lines[k];
    }
    console.log(string);  //log the same string outside the loop and the fatal error goes away
}

Answer 1

do npm install async --save
var async = require('async');

async.eachSeries(files , filesIteration , finishIteration);

function filesIteration(file , callBack){
    readFile(file , callBack);
}


function readFile(data , cb){
    var lines = fs.readFileSync(data).toString().split('\n');
    for(var k = 0; k < lines.length; k++){
        console.log(lines[k]);
        if(k === lines.length - 1){
            cb();
        }
    }
}

function finishIteration(){
    console.log('all files processed');
}