There are many questions about this, not least: jQuery version of array contains, a solution with the splice method and many more. However, they all seem complicated and annoying.
With the combined powers of javascript, jQuery and coffeescript, what is the very cleanest way to remove an element from a javascript array? We don't know the index in advance. In code:
a = [4,8,2,3]
a.remove(8) # a is now [4,2,3]
Failing a good built-in method, what is a clean way of extending javascript arrays to support such a method? If it helps, I'm really using arrays as sets. Solutions will ideally work nicely in coffeescript with jQuery support. Also, I couldn't care less about speed, but instead prioritize clear, simple code.
CoffeeScript:
Array::remove = (e) -> @[t..t] = [] if (t = @indexOf(e)) > -1
Which simply splices out the element at position t, the index where e was found (if it was actually found t > -1). Coffeescript translates this to:
Array.prototype.remove = function(e) {
var t, _ref;
if ((t = this.indexOf(e)) > -1) {
return ([].splice.apply(this, [t, t - t + 1].concat(_ref = [])), _ref);
}
};
And if you want to remove all matching elements, and return a new array, using CoffeeScript and jQuery:
Array::remove = (v) -> $.grep @,(e)->e!=v
which translates into:
Array.prototype.remove = function(v) {
return $.grep(this, function(e) {
return e !== v;
});
};
Or doing the same without jQuery's grep:
Array::filterOutValue = (v) -> x for x in @ when x!=v
which translates to:
Array.prototype.filterOutValue = function(v) {
var x, _i, _len, _results;
_results = [];
for (_i = 0, _len = this.length; _i < _len; _i++) {
x = this[_i];
if (x !== v) {
_results.push(x);
}
}
return _results;
};
Using vanilla Javascript:
Array.prototype.remove = function(elem) {
var match = -1;
while( (match = this.indexOf(elem)) > -1 ) {
this.splice(match, 1);
}
};
var a = [4, 8, 2, 3];
a.remove(8);
Only jQuery:
jQuery.removeFromArray = function(value, arr) {
return jQuery.grep(arr, function(elem, index) {
return elem !== value;
});
};
var a = [4, 8, 2, 3];
a = jQuery.removeFromArray(8, a);
This is really easy with jQuery:
var index = $.inArray("value", myArray);
if(index != -1)
{
myArray.splice(index, 1);
}
Notes:
splice returns the elements that were removed, so don't do myArray = myArray.splice(). myArray.splice(index,1) means "remove the array element at index 'index' from the array".
$.inArray returns the index in the array of the value you're looking for, or -1 if the value isn't in the array.