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JavaScript problem - properties assigned by setters are always undefined

  • 2 amsoshi
  • 2 sa na da wannan matsala
  • 1 view
  • Amsa ta ƙarshe daga jfd34

jfd34
jfd34
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Consider this JavaScript code: 

function foo(x) {
    var obj = { 
        set a(val) { document.write('Setting obj.a to ' + val + '\r\n'); }
    };
   
    obj.a = x;
    return obj.a + 2;
}

var n = foo(3);

The value of n will be NaN instead of the expected 5.

Is this a bug in Firefox or there is something wrong with the JavaScript code itself?

Consider this JavaScript code: function foo(x) { var obj = { set a(val) { document.write('Setting obj.a to ' + val + '\r\n'); } }; obj.a = x; return obj.a + 2; } var n = foo(3); The value of n will be NaN instead of the expected 5. Is this a bug in Firefox or there is something wrong with the JavaScript code itself?

An gyara daga jfd34

All Replies (2)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
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This at least works. 

function foo(x) {
var obj = { set aValue(val){ this.a=val; } };
obj.a = x;
return (obj.a + 2);
}
var n = foo(3);
alert(n);
jfd34
jfd34 Mai mallakar tambaya
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It is obvious why the code given by cor-el will work. The setter function is not called at all. It is similar to this: 

function foo(x) {
    var obj = {};
    obj.a = x;
    return (obj.a + 2);
}
var n = foo(3);
alert(n);

I want something which sets a property of an object using a setter function, and then retreives the value of that property.