I need to change array to a new array created inside a function.
function changeArr(a)
{
a=["hello"]; // don't work
//a.push("hello"); //works, but the real array pretty big (dont want copy)
}
var arr=[];
changeArr(arr);
console.log(arr); // should echo ["hello"]
It seems like all you really want to do is clear the array that is passed into the function, before appending to it:
function changeArr(a)
{
a.length = 0; // clear the array here if you don't care about the prev. contents
a.push("hello"); // this adds to the array that was passed in
}
a.length = 0; a[0] = "hello";.Inside the function changeArr(), a is only a local variable referencing the array you passed as an argument when calling this function. a=["hello"] makes this local variable reference a newly created and different array. This changes does not affect the original array passed in. What you want to do is likely what Miky Dinescu suggested: use the local variable to modify the original array but don't assign/attach anything new to it.
If you are trying to completely replace the array, you can use a return value.
function changeArr()
{
return ["hello"];
}
arr = changeArr();
If there is a reason you aren't doing this, explain and I'll adjust my answer.
You can use the splice method as such:
a.splice(0,a.length,"hello")
