var dasherize = compose(join('-'), toLower, split(' '), replace(/\s{2,}/ig, ' '));
dasherize('The world is a vampire');
// TypeError: Cannot read property 'apply' of undefinedWhat arguments is toLower called with?
What does split(' ') return?
const trace = require('composition-trace');
var dasherize = compose(join('-'), toLower, trace('after split'), split(' '), replace(/\s{2,}/ig, ' '));
// after split [ 'The', 'world', 'is', 'a', 'vampire' ]
dasherize('The world is a vampire');For more details, please see https://drboolean.gitbooks.io/mostly-adequate-guide/content/ch5.html#debugging