Except you would never get to use this method, because it will take years for all browser vendors to implement it, and even then, you still have a number of use

Except you would never get to use this method, because it will take years for all browser vendors to implement it, and even then, you still have a number of users that use for a reason or another Internet Explorer. You need to use a transpiler (like Typescript), but at this point, there no reason to implement that in the language, a transpiler can implement the feature by simply adding the method to the prototype of the object, like this: Array.prototype.at = function (i) { return i < 0 ? this[this.length + i] : this[i] }