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Discussion on: Avoid. Magic. Numbers

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grahamthedev profile image
GrahamTheDev • • Edited

I mean, I agree, but the example isn't a good one as really if you are going to use keyCode (which is deprecated by the way) then what is wrong with:

check(e) {
    if (e.keyCode === 13) { //13 is Enter Key
      this.attemptSendMessage(e);
    }
  }
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No memory assignment, no extra bytes in compiled code as comments are removed, readable by a human and no having to name it in the first place.

There is decent support for .key so you could use that and make it even easier!

check(e) {
    if (e.key == "Enter") {
      this.attemptSendMessage(e);
    }
  }
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Instead magic numbers are things like if you have a function and it has numeric values used for loops etc. it is better to define them at the top:

e.g.

function dealCards(){
   for(x = 0; x < 52, x++){
     //deal card;
  }
}
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Would be better as the following as it is easy to understand what "52" is!

function dealCards(){
   var deckSize = 52;
   for(x = 0; x < deckSize, x++){
     //deal card;
  }
}
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And even better in ES6 if you aren't stuck in the dark ages like me due to IE9 support 😁

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rockwell profile image
Ahmad khattab • • Edited

This is same thing, if you're using key then this case is already covered for you by the browser. Then you're good to go!. I was aware of the code thing. But you're correct. I have also added it to the post, huge thanks for pointing this out!.

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grahamthedev profile image
GrahamTheDev •

Added an example that is more in keeping with magic numbers and the sentiment of your post as I do agree, they are evil!

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rockwell profile image
Ahmad khattab •

Greatly agree, this too. Haven't the support for IE stopped? Microsoft has the new Edge as their flagship browser? You guys still are stuck with that monstrosity xD

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grahamthedev profile image
GrahamTheDev •

I work in accessibility and there are still a lot of people stuck on IE due to their screen reader etc. so I still support IE9+ (and by support I mean it all works fine but it might be a bit ugly or clunky in places, perfectly accessible but maybe missing a few "bells and whistles" afforded by modern browsers).

If IE11 support hasn't already stop it is due to soon so for most people it isn't a concern!