I am trying to read underscore.js. I’m going through the var each = _.each = _.forEach
method.
I understand strict equals (===
), but I do not understand what +obj.length
means.
else if (obj.length === +obj.length)
Here is a link to the code, and here is the full method:
var each = _.each = _.forEach = function(obj, iterator, context) {
if (obj == null) return;
if (nativeForEach && obj.forEach === nativeForEach) {
obj.forEach(iterator, context);
} else if (obj.length === +obj.length) {
for (var i = 0, l = obj.length; i < l; i++) {
if (iterator.call(context, obj[i], i, obj) === breaker) return;
}
} else {
for (var key in obj) {
if (_.has(obj, key)) {
if (iterator.call(context, obj[key], key, obj) === breaker) return;
}
}
}
};