Number as a variable name in javascript

Question

01. (function(){
02. function b(e){if(!d[e]){var f=d[e]={exports:{}};c[e].call(f.exports,a,f,b)}
03. return d[e].exports
04. }
05. var a=this,c=b.modules=[],d=b.cache=[];
06. c[0]=function(a,b,c)
07. {
08. var d=this;
09. 1;
10. var e=c(1),g=c(3).Builder,h=c(11);var i=c(10);
11. var j=c(15).Circle;var k = c(17).Friend; 
12. l=c(18).SearchFriends;c(19);

This is an fb app code that i have copied from fb friend circles, i am working in a different manner but was going through this script,where

FUNCTION c[0] has a variable 1 in it ...

How can bare numbers be used as variable names in javascript .. ?

possible duplicate of Valid Characters for JavaScript Variable Names — Dan D.
– Dan D., Commented Jul 3, 2011 at 22:56
c() is a function on lines 10-12, passed in on line 6 (third parameter), the number is just a parameter to that function. — Orbling
– Orbling, Commented Jul 3, 2011 at 22:58
@Dan D. dude that is an expression or a type it is not a duplicate of any other topic.. such a question has never been asked ..!! — Nina
– Nina, Commented Jul 3, 2011 at 23:23

Karoly Horvath · Accepted Answer · 2011-07-03 22:55:30Z

2

That's not a variable, that's an expression.

answered Jul 3, 2011 at 22:55

Karoly Horvath

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2 Comments

Nina Over a year ago

please elaborate.. how this expression evaluates ..?does that expression mean function c[0] returns true always ..?

Karoly Horvath Over a year ago

1 is an expression. so is 1+3. a couple of languages allow using expressions without actually using them (without assigning them to something or using them as a call parameter to a function, etc...). It's a no-operation

jfriend00 · Accepted Answer · 2011-07-03 23:09:52Z

2

Javascript variable names must begin with a letter or underscore or $. They may contain numbers, but not start with a number.

The statement you asked about:

1;

is a no-op. It's an expression that evaluates to a value of one, but since it isn't assigned to anything, it doesn't do anything. It doesn't declare a variable. Chances are it's a typo of some kind in the source you started with.

edited Jul 3, 2011 at 23:09

answered Jul 3, 2011 at 23:01

jfriend00

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4 Comments

user113716 Over a year ago

Variable names may also begin with $.

Nina Over a year ago

{view:"DetailCard",id:"card",pos:"w:88px h:95px",visible:!1} the expression has also been used inside the json array, may be its a boolean but it does appear like an expression

jfriend00 Over a year ago

@Nina. What is your question about that code? That is an object declaration that has attributes o.view, o.id, o.pos and o.visible.

Nina Over a year ago

i posted {//json content goes here} because the strange expression or variable is possibly also used inside the json, may be i am wrong

Edgar Villegas Alvarado · Accepted Answer · 2011-07-03 22:59:26Z

-1

They are not numbers, they are function calls.
For example, if you have

function c(num){
  if(num == 10) return "Edgar";
}

when you do:

c(10)

You get "Edgar" (the function evaluation).
Hope this helps. Cheers

answered Jul 3, 2011 at 22:59

Edgar Villegas Alvarado

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1 Comment

Nina Over a year ago

:) i asked about the variable/expression/typo inside the function c[0]

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