Nodejs exception handling example

This article describes the exception handling operation of Nodejs. Share it for your reference, as follows:

 = {
  expfun: function(flag) {
    if(flag == 0) {
      throw 'I'm an error';
    }
    return "success";
  }
}

//--------------------------------------
var fs = require('fs');
 = {
  readfile: function (path, recall) { //Asynchronous execution    (path, function (err, data) {
      if (err) {
        ("Async execution error:" + err);
        recall("The file does not exist, asynchronously execute error:" + err);//Asynchronous processing of exceptions      } else {
        //(());
        recall(data);
      }
    });
    ("===The asynchronous method has been executed===");
  },
  readImg: function (path, res) {
    (path, 'binary', function (err, filedata) {
      if (err) {
        (err);
        return;
      } else {
        ("Output File");
        (filedata, 'binary');
        ();
      }
    });
  }
}

var optfile = require('../model/');
function getRecall(req, res) {
  (200, {
    'Content-Type': 'text/html; charset=utf-8'
  });
  function recall(data) {
    (data);
    (''); //If you don't write, there is no end to http protocol  }
  return recall;
}
 = {
  login: function (req, res) {
    recall = getRecall(req, res);
    ('./view/', recall);
  },
  showimg: function (req, res) {
    (200, {
      'Content-Type': 'image/jpeg'
    });
    ("./view/", res);
  }
}

//-------------n9_exception.js---------------
/*
 Synchronous Capture &&Async Capture
 */
var http = require('http');
var url = require('url');
var router = require('./model/router');
var exception = require('./model/Exception');
(function (request, response) {
  if ( !== "/") { //Clear this second access    pathname = ().pathname;
    pathname = (/\//, ''); //Replace the previous one/    try {
      router[pathname](request, response);
      // data = (0);
      // (data);
      // ('');
    } catch (err) {
      ('Catched exception=' + err);
      (200, {
        'Content-Type': 'text/html; charset=utf-8'
      });
      (());
      ('');
    }
    ("server execution completed");
  }
}).listen(8000);
('Server running at http://127.0.0.1:8000/');

I hope this article will be helpful to everyone's nodejs programming.