Accessing array[-1]
In some programming languages, we can access array elements using negative indexes, counted from the end.
Like this:
let array = [1, 2, 3];
array[-1]; // 3, the last element
array[-2]; // 2, one step from the end
array[-3]; // 1, two steps from the endIn other words, array[-N] is the same as array[array.length - N].
Create a proxy to implement that behavior.
That’s how it should work:
let array = [1, 2, 3];
array = new Proxy(array, {
/* your code */
});
alert( array[-1] ); // 3
alert( array[-2] ); // 2
// Other array functionality should be kept "as is"let array = [1, 2, 3];
array = new Proxy(array, {
get(target, prop, receiver) {
if (prop < 0) {
// even if we access it like arr[1]
// prop is a string, so need to convert it to number
prop = +prop + target.length;
}
return Reflect.get(target, prop, receiver);
}
});
alert(array[-1]); // 3
alert(array[-2]); // 2