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JavaScript

Posted by Febby Gunawan
Febby Gunawan
14,075 Points

Code challenge: Call & Apply

Hi there, I'm stuck at this code challenge and I need some help from you guys. The challenge is "Set the 'greeting' variable, on line 29, by using the 'genericGreet' function in the context of 'andrew' with the array of arguments, 'args1'."

Here's my current code

 var genericGreet = function(name, mood) {
        name = name || "you";
        mood = mood || "good";
        return "Hello " + name + ", my name is " + this.name +
          " and I am in a " + mood + " mood!";
      }

      var andrew = {
        name: "Andrew"
      }

      var args1 = ["Michael", "awesome", ":)"];

      var greeting = genericGreet;
     greeting.apply(andrew,args1);

What did I do wrong. when I ran it on my own and I get ""Hello Michael, my name is Andrew and I am in a awesome mood!"

Thanks in advance.

4 Answers

Andrew Shook
Andrew Shook
31,709 Points

The problem is that you set the greetings variable equal to the function genericGreet() not the return value of the function. If you console log greeting from the code you have above, you should see that 

greeting = function(name, mood) {
        name = name || "you";
        mood = mood || "good";
        return "Hello " + name + ", my name is " + this.name +
          " and I am in a " + mood + " mood!";
      }

what you need to do is either:

var greeting = genericGreet.apply(andrew, arg1);

or

var greeting = genericGreet;
greeting = greeting.apply(andrew, arg1)
James Barnett
James Barnett
39,199 Points

Andrew Shook - Remember our goal here on the forum is give help not answers, next time try giving an explanation and/or a hint instead.

Need more explanation on the distinction check this out.

Andrew Shook
Andrew Shook
31,709 Points

Sorry, I wasn't sure how to explain it without showing an example.

James Barnett
James Barnett
39,199 Points

Andrew Shook - Answering questions well is a skill just like asking good questions.

In general ...

  • figure out how you'd fix the bugs in their code
  • diff the code
  • give them a few hints about where to look for the bugs.
  • Go online and search out the relevant documentation and/or tutorials to fill in the missing knowledge if they are using a procedure/data structure incorrectly
  • Give them links to best/most relevant example you found
Febby Gunawan
Febby Gunawan
14,075 Points
Febby Gunawan
Febby Gunawan
14,075 Points

Hi Andrew Shook , Thanks for the help. :) I wasn't sure what I do wrong but after I do the console.log it became clear for me that the greeting variable wasn't set the value of the function.

Andrew Shook
Andrew Shook
31,709 Points

Febby Gunawan, glad I come help.

Mark Thomas
Mark Thomas
8,174 Points
Mark Thomas
Mark Thomas
8,174 Points

Question: can someone explain the difference between call/apply in this instance?

scott duke
scott duke
5,033 Points
scott duke
scott duke
5,033 Points

Wow, I really need to start using the console.log(). @ Mark Thomas, I think that in this instance, one method can hold an array and the other, cannot.