James DiGioia

Purifying Functions - Functional Light JS v2 from Front-End Masters

December 1st, 2017

James DiGioia

function foo(x) {
	y++;
	z = x * y;
}

var y = 5, z;

foo(20);
z;		// 120

foo(25);
z;		// 175

function Foo(x, y) {
    var z;

    function foo(x) {
        y++;
        z = x * y;
    }

    foo(x);

    return [y, z];
}

function foo(x) {
    y++;
    z = x * y;
}

function Foo(x) {
    var [origY, origZ] = [y,z];
    foo(x);
    var [newY, newZ] = [y, z];
    [y, z] = [origY, origZ];
    
    return [newY, newZ];
}