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JavaScript JavaScript Foundations Arrays Methods: Part 1

Posted by Michael Nickey
Michael Nickey
Courses Plus Student 13,524 Points

Javascript Arrays Shift & Unshift

The question asks us to "On line 18, use a method on the 'spareWords' to set 'firstWord' to be first word of the 'spareWords' array whilst simultaneously removing it from the beginning of the array.".

The code that I have doesn't seem to work. 

    <script>
      var spareWords = ["The","chimney","sweep's","dog"];
      var saying = ["quick", "brown", "fox", "jumps", "over", "the", "lazy"];
      var firstWord = spareWords.unshift('firstWord').shift('firstWord');
      console.log(spareWords.toString());
      var lastWord = spareWords;
      saying;
      saying;
    </script>

When running this through the browser I see Uncaught TypeError: Object 5 has no method 'shift' index.html:18 (anonymous function)

Can we not string together methods? I'm even further confused because when I add simply 

      var firstWord = spareWords.shift();

I get an error that says I'm missing the shift method. Please help.

5 Answers

stephen antoni
stephen antoni
8,539 Points
stephen antoni
stephen antoni
8,539 Points

i think the instruction needs to be rephrased as i saw i wasn't the only one who got confused. /* use a method on the 'spareWords' to set 'firstWord' to be first word of the 'spareWords' array / - looks like you asked us to insert the new string ('firstWord') into the array - which naturally should use unshift method / whilst simultaneously removing it from the beginning of the array.". */ then removing that newly inserted array from the beginning of the list - using shift method

Kenan Memis
Kenan Memis
47,314 Points
Kenan Memis
Kenan Memis
47,314 Points

Correct!!

The instruction has to be rephrased since it is confusing. .shift() works perfect but I do not think that just using shift() method is what the instruction asks.

Denisse Cabieses
Denisse Cabieses
6,411 Points
Denisse Cabieses
Denisse Cabieses
6,411 Points

Hi Michael! I believe you can't string together methods. The correct way is just to use shift since it will take off the first value of the array. I used var firstWord = spareWords.shift(); and it worked for me. Hope this helps!

Jacob Miller
Jacob Miller
12,466 Points
Jacob Miller
Jacob Miller
12,466 Points

You can string together methods, but Denisse is correct that you only need to use .shift(), because it simultaneously removes the first item from an array and returns that item. Not sure why you were getting that error when you used only .shift(); it's working fine for me.

Jim Withington
Jim Withington
12,025 Points
Jim Withington
Jim Withington
12,025 Points

Yeah, this is weird—I feel like the wording could be much, much clearer, because it's actually making us create a variable called firstWord that also is not the first word of anything.

Code from the challenge again:

 var spareWords = ["The","chimney","sweep's","dog"];
      var saying = ["quick", "brown", "fox", "jumps", "over", "the", "lazy"];
      var firstWord = spareWords.shift();
Mahri Bahati
Mahri Bahati
2,254 Points
Mahri Bahati
Mahri Bahati
2,254 Points

The wording is very confusing. I started off trying to add "firstWord" as the first item in spareWords, and couldn't figure out why or how I was supposed to remove it at the same time. It was apparently much simpler than that. I think it would have been more clear if it said "set the value of 'firstWord' to be the first item of the 'spareWords' array while removing that item at the same time."

Thanks for the guidance!