From 6eec61e7df254037125c44cb8ada896496a5af51 Mon Sep 17 00:00:00 2001
From: Kenneth Shaw <kenneth.shaw@knq.io>
Date: Wed, 8 Feb 2017 23:16:28 +0700
Subject: [PATCH] Adding ElementNotPresent/WaitNotPresent query option/action

---
 examples/submit/main.go |  1 +
 sel.go                  | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/examples/submit/main.go b/examples/submit/main.go
index 36f00af..3020e5e 100644
--- a/examples/submit/main.go
+++ b/examples/submit/main.go
@@ -48,6 +48,7 @@ func submit(urlstr, sel, q string, res *string) cdp.Tasks {
 		cdp.WaitVisible(sel),
 		cdp.SendKeys(sel, q),
 		cdp.Submit(sel),
+		cdp.WaitNotPresent(`//*[@id="code_search"]/h2/svg`),
 		cdp.Text(`//*[@id="js-pjax-container"]/div[2]/div/div[2]/ul/li/p`, res),
 	}
 }
diff --git a/sel.go b/sel.go
index 967b37a..53b1755 100644
--- a/sel.go
+++ b/sel.go
@@ -27,6 +27,7 @@ tagname
 // Error types.
 var (
 	ErrNoResults   = errors.New("no results")
+	ErrHasResults  = errors.New("has results")
 	ErrNotVisible  = errors.New("not visible")
 	ErrVisible     = errors.New("visible")
 	ErrDisabled    = errors.New("disabled")
@@ -483,6 +484,18 @@ func ElementSelected(s *Selector) {
 	}))(s)
 }
 
+// ElementNotPresent is a query option to wait until no elements match are
+// present matching the selector.
+func ElementNotPresent(s *Selector) {
+	s.exp = 0
+	WaitFunc(func(ctxt context.Context, h cdp.FrameHandler, n *cdp.Node, ids ...cdp.NodeID) ([]*cdp.Node, error) {
+		if len(ids) != 0 {
+			return nil, ErrHasResults
+		}
+		return []*cdp.Node{}, nil
+	})(s)
+}
+
 // AtLeast is a query option to wait until at least n elements are returned
 // from the query selector.
 func AtLeast(n int) QueryOption {
@@ -525,6 +538,11 @@ func WaitSelected(sel interface{}, opts ...QueryOption) Action {
 	return Query(sel, append(opts, ElementSelected)...)
 }
 
+// WaitNotPresent waits until no elements match the specified selector.
+func WaitNotPresent(sel interface{}, opts ...QueryOption) Action {
+	return Query(sel, append(opts, ElementNotPresent)...)
+}
+
 const (
 	// visibleJS is a javascript snippet that returns true or false depending
 	// on if the specified node's offsetParent is not null.