Finding out how many times an array element appears

Question

I am new to JavaScript, I have been learning and practicing for about 3 months and hope I can get some help on this topic. I\'m making a poker game and what I\'m trying to d

Answer 1

When targeting recent enough browsers, you can use filter(). (The MDN page also provides a polyfill for the function.)

var items = [1, 2, 3, 4, 4, 4, 3];
var fours = items.filter(function(it) {return it === 4;});
var result = fours.length;

You can even abstract over the filtering function as this:

// Creates a new function that returns true if the parameter passed to it is 
// equal to `x`
function equal_func(x) {
    return function(it) {
        return it === x;
    }
}
//...
var result = items.filter(equal_func(4)).length;