Can't access property if object is taken from array
Question
This outputs "value", while with the commented out line it is "undefined". Why is that?
<!DOCTYPE html>
<html>
<body>
<script>
function Obj(property) {
this.property = property;
}
var arr = [new Obj("value")]
var obj = new Obj("value");
//var obj = arr.splice(0, 1);
console.log(obj.property);
</script>
</body>
</html>
3 answers
solution1
3 ACCPTED 2015-09-12 17:25:48
That's because splice() returns an array of elements:
console.log(obj[0].property);
As per the documentation (I've bolded the significant part that pertains to your example) :
An array containing the deleted elements. If only one element is removed, an array of one element is returned . If no elements are removed, an empty array is returned.
Working Example
function Obj(property) {
this.property = property;
}
var arr = [new Obj("value")]
var obj = arr.splice(0, 1);
console.log(obj[0].property);
// "value"
solution2
2 2015-09-12 17:34:24
this is because splice returns extracted array based on the parameters given, so obj becomes an array containing an element. so you must use console.log(obj[0].property);
solution3
0 2015-09-12 17:26:06
splice() function returns an array with spliced items . so access the property you should do:
var obj = arr.splice(0, 1)[0]; // extract the object first
console.log(obj.property);
OR
var obj = arr.splice(0, 1);
console.log(obj[0].property);
OR
var obj = arr[0];
console.log(obj.property);
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