Using fake operator overloading to simulate function composition

compOp.js

Function.prototype.valueOf = function(){
    id.fs.push(this)
}

function id(){
    var fs = []
    function f(x){
        for(var i=0,len=fs.length,v=x;i<len;v=fs[i++](v));
        return v
    }
    f.valueOf = function(){ id.fs = fs }
    return f
}

function sq(x){ return x + x }
function neg(x){ return -x }
function mult2(x){ return x * 2 }
function add1(x){ return x + 1 }

var f = id();
f >> sq >> neg >> mult2 >> add1;
f(2)