jquery - Using a variable for a key in a JavaScript object literal -


why following work?

<something>.stop().animate(     { 'top' : 10 }, 10 );

whereas doesn't work:

var thetop = 'top'; <something>.stop().animate(     { thetop : 10 }, 10 );

to make clearer: @ moment i'm not able pass css property animate function variable.

{ thetop : 10 } valid object literal. code create object property named thetop has value of 10. both following same:

obj = { thetop : 10 }; obj = { "thetop" : 10 };

in es5 , earlier, cannot use variable property name inside object literal. option following:

var thetop = "top";  // create object literal var aniargs = {};  // assign variable property name value of 10 aniargs[thetop] = 10;   // pass resulting object animate method <something>.stop().animate(     aniargs, 10   );

es6 defines computedpropertyname part of grammar object literals, allows write code this:

var thetop = "top",     obj = { [thetop]: 10 };  console.log(obj.top); // -> 10

you can test drive new syntax in recent versions of firefox, chrome , microsoft edge.


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