add waitUntilVisible()

src/document.js

@@ -352,6 +352,33 @@ class Document {
     return result
   }
 
+  async waitUntilVisible (selector) {
+    let check = null
+    let startTime = Date.now()
+    await new Promise((resolve, reject) => {
+      check = () => {
+        setTimeout(async () => {
+          try {
+            const now = Date.now()
+            if (now - startTime > this.chromy.options.waitTimeout) {
+              reject(new WaitTimeoutError('waitUntilVisible() timeout', selector))
+              return
+            }
+            const result = await this.visible(selector)
+            if (result) {
+              resolve(result)
+            } else {
+              check()
+            }
+          } catch (e) {
+            reject(e)
+          }
+        }, this.chromy.options.waitFunctionPollingInterval)
+      }
+      check()
+    })
+  }
+
   async type (expr, value) {
     await this.evaluate('document.querySelector(\'' + escapeSingleQuote(expr) + '\').focus()')
     const characters = value.split('')

test/wait.js

@@ -58,6 +58,25 @@ describe('wait', function() {
             done(e)
           })
   })
+  it('wait until visible', (done) => {
+    const chromy = new Chromy()
+    chromy.chain()
+          .goto('file://' + process.env.PWD + '/test_pages/wait.html')
+          .evaluate(() => {
+            setTimeout(() => {
+              let div = document.createElement('div')
+              div.innerText = 'text'
+              div.classList.add('newdiv')
+              document.body.appendChild(div)
+            }, 500)
+          })
+          .waitUntilVisible("div.newdiv")
+          .end()
+          .then(_ => done())
+          .catch(e => {
+            done(e)
+          })
+  })
   it('raise TimeoutError wait(function)', (done) => {
     const chromy = new Chromy({waitTimeout: 100})
     chromy.chain()