gistfile1.js

var add = TC()
    .Takes([TC.Number, TC.Number])
    .Returns(TC.Number)
    .By(function(a, b) { return a + b })
var divide = TC()
    .Takes([TC.Number, TC.Nonzero])
    .Returns(TC.Number)
    .By(function(a, b) { return a / b })
var sum = TC()
    .Takes([TC.Array(TC.Number)])
    .Returns(TC.Number)
    .By(function(xs) { return xs.reduce(add, 0) })
var charCount = TC()
    .Takes([TC.String])
    .Returns(TC.Object(TC.Number))
    .By(function(s) {
        return s
            .split('')
            .reduce(function(obj, c) {
                obj[c] = 1 + (c in obj ? obj[c] : 0)
                return obj
            }, Object.create(null))
    })