| 1 | // TodoMVC behaviour on top of the server-rendered page. Every action is |
| 2 | // still the page's own form post; this script sends it with fetch and |
| 3 | // the X-Todo-Fragment header, and the server answers with the new |
| 4 | // contents of section.todoapp instead of a 303. Without this script the |
| 5 | // forms post normally and nothing here is needed. |
| 6 | |
| 7 | const app = document.querySelector('.todoapp'); |
| 8 | |
| 9 | // Posts run one at a time, in the order they were made, so a quick |
| 10 | // toggle-then-delete can't land the other way round. |
| 11 | let queue = Promise.resolve(); |
| 12 | |
| 13 | function send(form) { |
| 14 | const body = new URLSearchParams(new FormData(form)); |
| 15 | const newTodo = form.querySelector('.new-todo'); |
| 16 | // TodoMVC clears the field once a todo is added. Clear it now, as the |
| 17 | // post goes, so anything typed while it is in flight is kept. |
| 18 | if (newTodo) newTodo.value = ''; |
| 19 | queue = queue |
| 20 | .then(() => fetch(form.action, { |
| 21 | method: 'POST', |
| 22 | body, |
| 23 | headers: { 'X-Todo-Fragment': '1' }, |
| 24 | credentials: 'same-origin', |
| 25 | })) |
| 26 | .then((res) => { |
| 27 | if (!res.ok) throw new Error(`${res.status} from ${form.action}`); |
| 28 | return res.text(); |
| 29 | }) |
| 30 | .then((html) => swap(html, newTodo !== null)) |
| 31 | .catch(() => location.reload()); |
| 32 | } |
| 33 | |
| 34 | // swap replaces the list with the server's markup, keeping whatever is |
| 35 | // in the new-todo field and its focus. After an add the field keeps |
| 36 | // focus, as TodoMVC does. |
| 37 | function swap(html, addsTodo) { |
| 38 | const input = app.querySelector('.new-todo'); |
| 39 | const typing = input.value; |
| 40 | const focused = addsTodo || document.activeElement === input; |
| 41 | const [start, end] = [input.selectionStart, input.selectionEnd]; |
| 42 | app.innerHTML = html; |
| 43 | const next = app.querySelector('.new-todo'); |
| 44 | if (typing) next.value = typing; |
| 45 | if (focused) { |
| 46 | next.focus(); |
| 47 | if (typing) next.setSelectionRange(start, end); |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | app.addEventListener('submit', (e) => { |
| 52 | e.preventDefault(); |
| 53 | send(e.target); |
| 54 | }); |
| 55 | |
| 56 | // The checkboxes are the page's own controls with JavaScript on. |
| 57 | app.addEventListener('change', (e) => { |
| 58 | if (e.target.matches('.toggle, .toggle-all')) send(e.target.form); |
| 59 | }); |
| 60 | |
| 61 | // Double-click a title to edit it. |
| 62 | app.addEventListener('dblclick', (e) => { |
| 63 | const label = e.target.closest('.todo-list label'); |
| 64 | if (!label) return; |
| 65 | const li = label.closest('li'); |
| 66 | const input = li.querySelector('.edit'); |
| 67 | li.classList.add('editing'); |
| 68 | input.focus(); |
| 69 | input.setSelectionRange(input.value.length, input.value.length); |
| 70 | }); |
| 71 | |
| 72 | // Enter saves (the edit form's own submit), Escape cancels. |
| 73 | app.addEventListener('keydown', (e) => { |
| 74 | if (!e.target.matches('.edit') || e.key !== 'Escape') return; |
| 75 | const input = e.target; |
| 76 | const li = input.closest('li'); |
| 77 | input.value = input.defaultValue; |
| 78 | li.classList.remove('editing'); |
| 79 | input.blur(); |
| 80 | }); |
| 81 | |
| 82 | // Leaving the editor saves it, unless Escape already closed it. |
| 83 | app.addEventListener('focusout', (e) => { |
| 84 | if (!e.target.matches('.edit')) return; |
| 85 | const li = e.target.closest('li'); |
| 86 | if (!li.classList.contains('editing') || li.dataset.saving) return; |
| 87 | li.dataset.saving = '1'; |
| 88 | send(e.target.form); |
| 89 | }); |
| 90 | |
| 91 | // Enter's submit also blurs as the list is replaced; mark it so the |
| 92 | // focusout above doesn't post the same edit twice. |
| 93 | app.addEventListener('submit', (e) => { |
| 94 | const li = e.target.closest('li'); |
| 95 | if (li) li.dataset.saving = '1'; |
| 96 | }, true); |
| 97 | |
amadan