What follows is the polyfill for Array.prototype.find
on MDN.
What purpose does the unsigned right shift assignment operator (>>>
) serve in this code? (I can only think conversion to 32-bit integer?!)
if (!Array.prototype.find) {
Object.defineProperty(Array.prototype, 'find', {
value: function(predicate) {
'use strict';
if (this == null) {
throw new TypeError('Array.prototype.find called on null or undefined');
}
if (typeof predicate !== 'function') {
throw new TypeError('predicate must be a function');
}
var list = Object(this);
var length = list.length >>> 0;
var thisArg = arguments[1];
var value;
for (var i = 0; i < length; i++) {
value = list[i];
if (predicate.call(thisArg, value, i, list)) {
return value;
}
}
return undefined;
}
});
}
MDN.