Declaring a local variable

I want to declare a local variable as such:

(var n=1)

Mostly so I can manipulate the order it gets evaluated in.

Eg Then I could do

var increaseadNumber = (
    ar={
        inc开发者_Go百科:function(n){
            return n+1
        },
        dec:function(n){
            return n+2
        }
   }
).inc(1);
console.log(ar)//the object
console.log(increaseadNumber )//2

But, in my example ar is in the global namespace, and

var increaseadNumber = (
  var ar={
        inc:function(n){
            return n+1
        },
        dec:function(n){
            return n+2
        }
   }
).inc(1);//syntax error

generates "SyntaxError: Unexpected token var"

Granted I could declare this over 2 statements, but I would prefer to it with 1 statement.

Why not separate it into two lines?

var ar={inc:function(n){return n+1},dec:function(n){return n+2}};
ar.inc(1);

And add some sensible white space while you're at it:

var ar = {
    inc: function(n) {
        return n + 1
    },
    dec: function(n) {
        return n + 2
    }
};
ar.inc(1);

Or if you're really whitespace-averse, here's a compromise:

var ar = {
    inc: function(n) { return n + 1 },
    dec: function(n) { return n + 2 }
};
ar.inc(1);

The var keyword cannot follow an open parenthesis except in for (var ...). Maybe wrap the expression in a function:

ar = (function (n) {
  return /* compute the value for ar here */;
})(1)

You can split the statement into:

var ar={inc:function(n){return n+1},dec:function(n){return n+2}}; ar.inc(1);

var ar = { 
  inc: function (n) { return n+1 },
  dec: function (n) { return n+2 } 
};
ar.inc(1);

Just declare it locally and invoke it in a seperate expression.

If you really want one expression I would recommend you declare a throwaway local variable __

var ar = { 
  inc: function (n) { return n+1 },
  dec: function (n) { return n+2 } 
}, __ = ar.inc(1);

The only way to invoke multiple expressions where one is a variable declaration is to declare multiple variables

If you want a local variable try declare it in a function,

(function () {
    var ar={inc:function(n){return n+1},dec:function(n){return n+2}};
    return ar;
})().inc(1)

not sure what is is you want to do, but this IIF (Immediately Invoked Function) may be an idea for you? Added a bit of spacing, which is ... advisable if you want to maintain your code.

   alert(
    (function(n){
     n = n || 1;
     return {
              inc: function(n){ return n+1; },
              dec: function(n){ return n+2; }
            };

    }(1)).inc(1)
   ); //=> 2