const hide = el => el.classList.add('d-none'); const show = el => el.classList.remove('d-none'); const setupCollapsibleInput = el => { const collapsedEl = el.querySelector('.js-collapsed'); const expandedEl = el.querySelector('.js-expanded'); const collapsedInputEl = collapsedEl.querySelector('textarea,input,select'); const expandedInputEl = expandedEl.querySelector('textarea,input,select'); const formEl = el.closest('form'); const collapse = () => { hide(expandedEl); show(collapsedEl); }; const expand = () => { hide(collapsedEl); show(expandedEl); }; // NOTE: // We add focus listener to all form inputs so that we can collapse // when something is focused that's not the expanded input. formEl.addEventListener('focusin', e => { if (e.target === collapsedInputEl) { expand(); expandedInputEl.focus(); } else if (!el.contains(e.target) && !expandedInputEl.value) { collapse(); } }); }; /** * Usage in HAML * * .js-collapsible-input * .js-collapsed{ class: ('d-none' if is_expanded) } * = input * .js-expanded{ class: ('d-none' if !is_expanded) } * = big_input */ export default () => { Array.from(document.querySelectorAll('.js-collapsible-input')).forEach(setupCollapsibleInput); };