TypeError: property Array.prototype.splice.call(...) is non-configurable and can't be deleted

Question

When I attempt to load my page in FF I get this error:

TypeError: property Array.prototype.splice.call(...) is non-configurable and can't be deleted

Here is the prototype

   HTMLElement.prototype.selectorAll = function (selectors, fun) {

        var sels = Array.prototype.splice.call(this.querySelectorAll(selectors), 0)
        if (!fun) { return sels; }; fun.call(sels);
    };

How do I fix this error?

Answer 1

Use slice rather than splice to just create a new Array from the original collection.

var sels = Array.prototype.slice.call(this.querySelectorAll(selectors), 0)

The error is because splice is also attempting to modify the original collection:

var a = [ 1, 2, 3, 4 ];

a.slice(0);
console.log(a); // [ 1, 2, 3, 4 ]

a.splice(0);
console.log(a); // []

And the NodeList returned from querySelectorAll() has a non-configurable property that splice can't alter as it expects.