Creates a unary function with an optional transformer callback from a callable and a transformer fallback
npm i unary-with-optional-callback
var unaryWithOptionalCallback = require('unary-with-optional-callback');
function transformableSqrt(transformer, x) {
return transformer(Math.sqrt(x));
}
var integerSqrt = unaryWithOptionalCallback(transformableSqrt, Math.floor);
integerSqrt(8); // => 2
integerSqrt(8, Math.ceil); // => 3