can not access the array of an object

Question

Below are my javascript code:

function A (no ){
 this.no=no;
};
function AController (){
 this.amount =0;
 this.array=[]; 
};
AController.prototype.initArray=function(){
 for(var i=1;i<=this.amount;i++){
 var tem=new A(i) ;
 this.array.push(tem);
 }
};

then I execute somewhere

var f=new AController();
f.amount=2;
f.initArray();
for(var i=1 ;i<=2;i++){ 
 f.array[i].no=0; 
}

but it always reports

JS: TypeError: f.array[i] is undefined

your comment welcome

• Lix: Um... are you sure the problem is with the code you have posted? I don't see f.cardArray anywhere...
• Naftali: Ummm nowhere in your code do you use f.cardArray
• Xynariz: In addition, as was mentioned in a now-deleted answer, you should start at a 0 index when iterating through arrays - array[2] in an array of length 2 will return an error.
• arachide: I edited question, f.cardArray should be f.array. sza's answer is correct

Answer 1

You need to loop from 0

for (var i = 0; i < 2; i++) {
 f.array[i].no = 0;
}

After push operations, the array is [A(1), A(2)], so f.array[2] will be undefined. Since you tried to assign no property on the 3rd object in the array which is undefined, hence you got that error.

• Virus721: Actually he has filled his array the same way he is reading it, so it should work shouldn't it ?
• collapsar: @Virus721: not for the last array element.
• Virus721: @collapsar Ho i just realized he used .push() instead [], but in that case it would have worked.
• collapsar: @Virus721: yes, it would have.