1 files changed, 87 insertions, 0 deletions
diff --git a/public/javascripts/autocomplete.js b/public/javascripts/autocomplete.js
new file mode 100644
index 0000000..71fb17d
--- /dev/null
+++ b/public/javascripts/autocomplete.js
@@ -0,0 +1,87 @@
+const EventEmitter = require('events')
+
+const self = new EventEmitter()
+
+self._items = []
+self._selectedItemIndex = -1
+
+self._nodes = {
+  search: document.querySelector('#search'),
+  input: document.querySelector('input[type="search"]'),
+  autocomplete: document.querySelector('.autocomplete')
+}
+
+self.getSelectedItem = function () {
+  if (self.getItems() === []) return
+
+  if (self.getSelectedItemIndex() === -1) {
+    return self.getItems()[0]
+  } else {
+    return self.getItems()[self.getSelectedItemIndex()]
+  }
+}
+
+self.getSelectedItemIndex = function () {
+  return self._selectedItemIndex
+}
+
+self.getItems = function () {
+  return self._items
+}
+
+self.removeAllItems = function () {
+  while (self._nodes.autocomplete.firstChild) {
+    self._nodes.autocomplete.removeChild(self._nodes.autocomplete.firstChild)
+  }
+  self._items = []
+  self._selectedItemIndex = -1
+}
+
+self.addItem = function (item) {
+  const listItem = document.createElement('li')
+  listItem.textContent = item.value
+  self._nodes.autocomplete.appendChild(listItem)
+  self._items.push(item)
+}
+
+self._moveSelected = function (shift) {
+  if (self._selectedItemIndex + shift >= self.getItems().length) {
+    self._selectedItemIndex = -1
+  } else if (self._selectedItemIndex + shift < -1) {
+    self._selectedItemIndex = self.getItems().length - 1
+  } else {
+    self._selectedItemIndex += shift
+  }
+
+  for (let i = 0; i < self.getItems().length; i++) {
+    self._nodes.autocomplete.children[i].classList.remove('selected')
+  }
+  if (self._selectedItemIndex >= 0) {
+    self._nodes.autocomplete
+        .children[self._selectedItemIndex].classList.add('selected')
+  }
+}
+
+self._handleItemClick = function (event) {
+  if (!self._nodes.autocomplete.contains(event.target)) return
+  const itemIndex = Array.prototype.indexOf
+      .call(self._nodes.autocomplete.children, event.target)
+  self._selectedItemIndex = itemIndex
+  self.emit('select', self.getSelectedItem())
+}
+
+self._handleKeydown = function (event) {
+  if (event.key === 'ArrowDown' || event.key === 'ArrowUp') {
+    event.preventDefault()
+    if (event.key === 'ArrowDown') {
+      self._moveSelected(1)
+    } else if (event.key === 'ArrowUp') {
+      self._moveSelected(-1)
+    }
+  }
+}
+
+self._nodes.autocomplete.addEventListener('click', self._handleItemClick)
+self._nodes.input.addEventListener('keydown', self._handleKeydown)
+
+module.exports = self