1 files changed, 75 insertions, 0 deletions
diff --git a/bh20simplewebuploader/static/main.js b/bh20simplewebuploader/static/main.js
index 96199a0..a67d3df 100644
--- a/bh20simplewebuploader/static/main.js
+++ b/bh20simplewebuploader/static/main.js
@@ -45,3 +45,78 @@ function displayForm() {
   }
   fillFormSpot.classList.add("invisible");
 }
+
+/**
+ * Add another form field to the group this button is part of.
+ */
+function addField(e) {
+  // Find our parent field-group div
+  let fieldGroup = this.parentElement
+  
+  // Get its keypath
+  let keypath = fieldGroup.dataset.keypath
+  
+  // Find its last field child
+  let existingFields = fieldGroup.getElementsByClassName('field')
+  let templateField = existingFields[existingFields.length - 1]
+  
+  // Get its number
+  let fieldNumber = templateField.dataset.number
+  
+  // Duplicate it
+  let newField = templateField.cloneNode(true)
+  
+  // Increment the number and use the keypath and number to set IDs and cross
+  // references.
+  // TODO: Heavily dependent on the form field HTML. Maybe we want custom
+  // elements for the labeled controlsd that know how to be list items?
+  fieldNumber++
+  newField.dataset.number = fieldNumber
+  let newID = keypath + '[' + fieldNumber + ']'
+  let newControl = newField.getElementsByClassName('control')[0]
+  newControl.id = newID
+  newControl.setAttribute('name', newID)
+  let newLabel = newField.getElementsByTagName('label')[0]
+  newLabel.setAttribute('for', newID)
+  
+  // Find the minus button
+  let minusButton = fieldGroup.getElementsByClassName('remove-field')[0]
+  
+  // Put new field as a child before the minus button
+  fieldGroup.insertBefore(newField, minusButton)
+  
+  // Enable the minus button
+  minusButton.classList.remove('hidden')
+}
+
+/**
+ * Remove the last form field from the group button is part of.
+ */
+function removeField(e) {
+  // Find our parent field-group div
+  let fieldGroup = this.parentElement
+  
+  // Find its field children
+  let existingFields = fieldGroup.getElementsByClassName('field')
+  
+  if (existingFields.length > 1) {
+    // There is a last field we can safely remove.
+    let lastField = existingFields[existingFields.length - 1]
+    fieldGroup.removeChild(lastField)
+  }
+  
+  if (existingFields.length <= 1) {
+    // Collection auto-updates. Now there's only one element. Don't let the
+    // user remove it. If they don't want it, they can leave it empty.
+    this.classList.add('hidden')
+  }
+}
+
+// Find all the add and remove field buttons and hook up the listeners.
+for (let button of document.getElementsByClassName('add-field')) {
+  button.addEventListener('click', addField)
+}
+for (let button of document.getElementsByClassName('remove-field')) {
+  button.addEventListener('click', removeField)
+}
+