javascript - Node Stream: Not passing Callback Function a Value -



javascript - Node Stream: Not passing Callback Function a Value -

i working on nodeschool.io's learnyounode http client exercise.

this task:

write programme performs http request url provided first command-line argument. write string contents of each "data" event response new line on console (stdout).

my solution was:

var http = require("http"); var url = process.argv[2]; http.get(url, function(res){ res.setencoding('utf8'); res.on('data', function(data){ console.log(data); }) });

this worked, curious why suggested solution works. how console.log , console.error using data or error objects. don't appear passed callback function.

var http = require('http') http.get(process.argv[2], function (response) { response.setencoding('utf8') response.on('data', console.log) response.on('error', console.error) })

by using response.on('data', console.log), registering event listener trigger console.log() function it's callback. response object event emitter, , when http.get request receives info remote server emits 'data' event picked listener. event implicitly passes received info first parameter console.log callback function on listener. same process holds true 'error' event.

javascript node.js callback

Comments

Post a Comment

Popular posts from this blog

c - Compilation of a code: unkown type name string -

c - Compilation of a code: unkown type name string - i have next lines of code compiler says following: "unknown type name 'string'" both in declaration , definition of function. can tell me what's wrong? thanks. #include <stdio.h> #include <stdlib.h> #include <string.h> void frecognizeclient(string *actualclient) there no string type in c. need utilize array so: char array[10]; then can pass in function: void frecognizeclient(char *actualclient); c arrays string compilation
Read more

java - Bypassing "final local variable defined in an enclosing type" -

java - Bypassing "final local variable defined in an enclosing type" - i'm writing programme , i'm getting "the final local variable asd cannot assigned, since it's defined in enclosing type". i provide illustration not code produces error aswell. have arraylist utilize later (if define within button can't utilize later on), outside of button, pressing button should give values arraylist. in illustration "create new arraylist" cause same problem. button btn = new button("asd"); final arraylist asd = new arraylist(); btn.setonaction(new eventhandler<actionevent>() { public void handle(final actionevent event) { asd = new arraylist(); //here's error.. } }); clear arraylist , add together values. java javafx
Read more

json - Hibernate and Jackson (java.lang.IllegalStateException: Cannot call sendError() after the response has been committed) -

json - Hibernate and Jackson (java.lang.IllegalStateException: Cannot call sendError() after the response has been committed) - hello have problem hibernate , jackson. have 2 pojos @entity @table(name = "users") public class user implements serializable { static final long serialversionuid = 4235637833262722256l; @id @generatedvalue private int id; @column(name = "creation_date") private date creationdate; @column(name = "first_name") private string firstname; @column(name = "last_name") private string lastname; @version @column(name = "version") private int version; @column(name = "e_mail") private string email; @column(name = "enabled") private boolean enabled; @column(name = "login") private string login; @column(name = "password") private string password; @jsonmanagedreference("role") @onetomany(mappedby = "user", cascade = cascadetype.all,fetch = fetchtyp...
Read more