From f6b619aab1d6a0804194f0b6fcbbcdf3963ec1d2 Mon Sep 17 00:00:00 2001
From: Christopher Chedeau <vjeuxx@gmail.com>
Date: Tue, 5 Jul 2016 10:22:56 -0700
Subject: [PATCH] [flow] isTextInputElement (#7075)

Summary:

I had to cast into any because flow doesn't think that checking the lowercase version of nodeName is a valid way to refine the variable from HTMLElement to HTMLInputElement. I'm also not confident enough in changing the implementation to an instanceof HTMLInputElement to please flow. It also takes care of the null check in the process.

The `nodeName &&` condition wasn't useful since the two branches are checking it against concrete values and actually makes the type different since nodeName is not a boolean per se. I replaced them with if conditions to make it clearer what it actually did instead of doing boolean logic tricks.

It is unclear why I had to type supportedInputTypes, see this internal post for a discussion: https://www.facebook.com/groups/flowtype/permalink/1084168611631753/

The only difference in behavior is that I now explicitely convert to boolean the object dereference via `!!`.

Test Plan:
npm run flow
Careful inspection of the code

Reviewers: @zpao @spicyj
(cherry picked from commit 309215fc40e81354bd06d11e108866f87156fb55)
---
 .../shared/utils/isTextInputElement.js        | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/renderers/shared/utils/isTextInputElement.js b/src/renderers/shared/utils/isTextInputElement.js
index 0b0075dca1..c2635ac5e2 100644
--- a/src/renderers/shared/utils/isTextInputElement.js
+++ b/src/renderers/shared/utils/isTextInputElement.js
@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @providesModule isTextInputElement
+ * @flow
  */
 
 'use strict';
@@ -14,7 +15,7 @@
 /**
  * @see http://www.whatwg.org/specs/web-apps/current-work/multipage/the-input-element.html#input-type-attr-summary
  */
-var supportedInputTypes = {
+var supportedInputTypes: {[key: string]: true | void} = {
   'color': true,
   'date': true,
   'datetime': true,
@@ -32,12 +33,18 @@ var supportedInputTypes = {
   'week': true,
 };
 
-function isTextInputElement(elem) {
+function isTextInputElement(elem: ?HTMLElement): bool {
   var nodeName = elem && elem.nodeName && elem.nodeName.toLowerCase();
-  return nodeName && (
-    (nodeName === 'input' && supportedInputTypes[elem.type]) ||
-    nodeName === 'textarea'
-  );
+
+  if (nodeName === 'input') {
+    return !!supportedInputTypes[((elem: any): HTMLInputElement).type];
+  }
+
+  if (nodeName === 'textarea') {
+    return true;
+  }
+
+  return false;
 }
 
 module.exports = isTextInputElement;