Add optional password to the download url

app/templates/uploadPassword.js

@@ -0,0 +1,37 @@
+const html = require('choo/html');
+
+module.exports = function(state, emit) {
+  const file = state.storage.getFileById(state.params.id);
+  const div = html`
+  <div class="selectPassword">
+    <div>
+      <input id="addPassword" type="checkbox" onchange=${togglePasswordInput}/>
+      <label for="addPassword">${state.translate(
+        'requirePasswordCheckbox'
+      )}</label>
+    </div>
+    <form class="setPassword hidden" onsubmit=${setPassword}>
+      <input id="unlock-input"
+        autocomplete="off"
+        placeholder="${state.translate('unlockInputPlaceholder')}"/>
+      <input type="submit"
+        id="unlock-btn"
+        class="btn"
+        value="${state.translate('addPasswordButton')}"/>
+    </form>
+  </div>`;
+
+  function togglePasswordInput() {
+    document.querySelector('.setPassword').classList.toggle('hidden');
+  }
+
+  function setPassword(event) {
+    event.preventDefault();
+    const password = document.getElementById('unlock-input').value;
+    if (password.length > 0) {
+      emit('password', { password, file });
+    }
+  }
+
+  return div;
+};