用拼接交换元素位置后，Javascript数组元素indexOf为-1

Question

Our array has two elements of type object like this:

array = [{Member1: "Value1"},{Member2: "Value2"}];

When I get the index of second object like this:

var index = array.indexOf(obj);

I get 1 as the result, which is fine. But when I swap the two elements like this to shift this object from right to left and the other 0 index object from left to right:

var new_index = index - 1;
array.splice(index, 0, array.splice(new_index, 1)[0]);

and try to get the index of the same object (which I know is present in the array and only its index is 0 now) I get -1 (not found) as the result. Whats the problem here?

Answer 1

As you want to swap, rather than splicing it may be better to use a temporary variable.

var array = [{Member1: "Value1"},{Member2: "Value2"}],
    obj = array[1];

function swap(arr, i, j) {
    var t = arr[i];
    arr[i] = arr[j];
    arr[j] = t;
    return arr;
}

console.log('before swap', array.indexOf(obj)); // 1

swap(array, 0, 1);
console.log('after swap', array.indexOf(obj)); // 0

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EDIT Just tried your code though and I get the expected result of 0 , maybe you've done something to the reference obj is pointing at between the two