Examples for using anonymouse functions with functional programming in Javascript

index.html

<div>
    <p id="text1"></p>
    <p id="text2"></p>
</div>

script.js

function forEach(array, fn) {
    var result = [];
	for (var i=0; i<array.length; i++) {
    	result.push(fn(array[i]));	   
    }
    return result;
}

var data = ['hello', 'ms', 'robinson'];

var iteratedData = forEach(data, function(item) {
	return item.length;    
})

document.getElementById('text1').innerHTML = iteratedData;

function filter(array, fn) {
    var result = [];
	for (var i=0; i<array.length; i++) {
     	if (fn(array[i])) {
            result.push(array[i]);
        } 
    }
    return result;
}

var datum = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

var newData = filter(datum, function(item) {
   if (item%3===0) {
    	return true;   
   }
});

document.getElementById('text2').innerHTML = newData;