do not re-validate on blur if already validated

In testing #76 in
GitHub.com, we discovered cases where input would be re-validated
on blur even if the input had not changed. This PR updates our
valid and invalid code paths to only validate on blur if the input
has not otherwise been already validated.

src/auto-check-element.ts

@@ -214,12 +214,19 @@ function handleChange(checker: () => void, event: Event) {
   const autoCheckElement = input.closest('auto-check')
   if (!(autoCheckElement instanceof AutoCheckElement)) return
 
+  if (event.type === 'input') {
+    autoCheckElement.setAttribute('dirty', '')
+  }
+
   if (input.value.length === 0) return
 
   if (
     (event.type !== 'blur' && !autoCheckElement.onlyValidateOnBlur) || // Existing default behavior
-    (event.type === 'blur' && autoCheckElement.onlyValidateOnBlur) || // Only validate on blur if only-validate-on-blur is set
-    (autoCheckElement.onlyValidateOnBlur && autoCheckElement.validateOnKeystroke) // Only validate on key inputs in only-validate-on-blur mode if validate-on-keystroke is set (when input is invalid)
+    (event.type === 'blur' &&
+      autoCheckElement.onlyValidateOnBlur &&
+      !autoCheckElement.validateOnKeystroke &&
+      autoCheckElement.hasAttribute('dirty')) || // Only validate on blur if only-validate-on-blur is set, input is dirty, and input is not current validating on keystroke
+    (event.type === 'input' && autoCheckElement.onlyValidateOnBlur && autoCheckElement.validateOnKeystroke) // Only validate on key inputs in only-validate-on-blur mode if validate-on-keystroke is set (when input is invalid)
   ) {
     setLoadingState(event)
     checker()
@@ -326,6 +333,8 @@ async function check(autoCheckElement: AutoCheckElement) {
 
   state.controller = makeAbortController()
 
+  autoCheckElement.removeAttribute('dirty')
+
   try {
     const response = await fetchWithNetworkEvents(autoCheckElement, url.toString(), {
       credentials: 'same-origin',

test/auto-check.js

@@ -60,6 +60,18 @@ describe('auto-check element', function () {
       assert.deepEqual(events, ['auto-check-start'])
     })
 
+    it('does not emit on blur if input has not changed after initial blur', async function () {
+      const events = []
+      input.addEventListener('auto-check-start', event => events.push(event.type))
+      triggerInput(input, 'hub')
+      triggerBlur(input)
+
+      await once(input, 'auto-check-complete')
+      triggerBlur(input)
+
+      assert.deepEqual(events, ['auto-check-start'])
+    })
+
     it('emits on input change if input is invalid after blur', async function () {
       const events = []
       input.addEventListener('auto-check-start', event => events.push(event.type))
@@ -74,6 +86,23 @@ describe('auto-check element', function () {
       assert.deepEqual(events, ['auto-check-start', 'auto-check-start', 'auto-check-start'])
     })
 
+    it('does not emit on blur if input is invalid', async function () {
+      const events = []
+      input.addEventListener('auto-check-start', event => events.push(event.type))
+
+      checker.src = '/fail'
+      triggerInput(input, 'hub')
+      triggerBlur(input)
+      await once(input, 'auto-check-complete')
+
+      triggerInput(input, 'hub2')
+      triggerBlur(input)
+
+      triggerInput(input, 'hub3')
+
+      assert.deepEqual(events, ['auto-check-start', 'auto-check-start', 'auto-check-start'])
+    })
+
     afterEach(function () {
       document.body.innerHTML = ''
       checker = null