Question

155

Default Values for JSON in javascript

rated 0 times [ 162] [ 7] / answers: 1 / hits: 17499 / 15 Years ago, sun, september 6, 2009, 12:00:00

In the code:

slider.init({

 foo: bar

});



var slider={

 init:function(data){

 }

}

If I use data.foo, I will get bar.

Supposing I have an optional variable called fish which can be included in the JSON variable. If I reference data.fish, I will be told that it is undefined or an error will be thrown or something. Is there a way that I can assign a default value to fish so that when I request data.fish, even though it is not set in the parameter, I will get a default value?

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alexander

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answered 15 Years ago skylerselenem · Accepted Answer

You can use the or operator to assign default values in case the aren't defined, for example:

var slider = {

 init:function(data){

   var fish = data.fish || default value;

 }

}

Or you can make an extend function, to merge two objects, similar to the jQuery extend function:

function extend (obj1, obj2) { 

  var result = obj1, val;

  for (val in obj2) {

    if (obj2.hasOwnProperty(val)) {

      result[val] = obj2[val];

    }

  }

return result;

}



var defaults = {val1: 1, val3: 3, fish: 'fish'};

extend(defaults, {val2: 2}); // returns Object val1=1 val3=3 fish=fish val2=2