Higher-order Functions—Callback Functions

by Ivan Gerasimenko

JavaScript

function compareNumbers(x, y) {
    if (x < y)
        return -1;
    if (x > y)
        return 1;
    return 0;
}

var arr = [4,1,6,3,2,9,7].sort( //<-- Higher-order func
    compareNumbers); //<--Callback func

console.log(arr);

// and anonimous function as callback function
var arr1 = [4,1,6,3,2,9,7].sort(
    function(x, y) {
        if(x < y) 
            return -1;
        if(x > y) 
            return 1;
        return 0;
    }
);

console.log(arr1);