node异步读取文件的陷阱

来源：互联网发布：mac os无法安装编辑：程序博客网时间：2024/06/18 17:45

node是可以异步读取文件，但是如果一下子异步读取的数量过大，则会抛出20错误

以下列出3种读取方式：同步，异步转同步，数量约束的异步

var t1, t2;t1 = +new Date;fileList.forEach(function(n, i) {var data = fs.readFileSync(n, {encoding: "utf-8"});if (data && data.indexOf && data.indexOf("templateUrl: 'templates/widget-label.html'") >= 0) {console.log(n);}});t2 = +new Date;console.log(t2 - t1);t1 = +new Date;async.eachSeries(fileList, function(n, callback) {fs.readFile(n, "utf-8", function() {// to do callback(null, null);})}, function(err) {t2 = +new Date;console.log(t2 - t1);console.log("eachSeries end");})/*t1 = +new Date;fileList.forEach(function(n, i) {fs.readFile(n, "utf-8", function(err, data) {// to do });});t2 = +new Date;console.log(t2 - t1);*/t1 = +new Date;async.eachLimit(fileList, 500, function(n, callback) {fs.readFile(n, "utf-8", function() {// to do callback(null, null);})}, function(err) {t2 = +new Date;console.log(t2 - t1);console.log("eachLimit end");});

时间分别为2564，4007，1207

（我的文件夹下有3000个文件）

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