text-transform-functional.js

const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args)));

export const trim = text => text.trim();
export const toLowerCase = text => text.toLowerCase();
export const capitalize = text => text.charAt(0).toUpperCase() + text.slice(1);
export const addExclamationMark = text => text + '!';
export const addPunctuation = text => text + '.';

export const makeImportant = compose(addExclamationMark, capitalize, toLowerCase, trim);
export const makeUnimportant = compose(addPunctuation, toLowerCase, trim);