From bde4cf5656f48b8678f39cfd5307edad535b0574 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mario=20Beltra=CC=81n=20Alarco=CC=81n?= <belco90@gmail.com>
Date: Tue, 31 Mar 2020 11:31:42 +0200
Subject: [PATCH 1/2] feat(waitFor): improve error message for non-function
 callbacks

---
 src/__tests__/wait-for.js | 6 ++++++
 src/wait-for.js           | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/src/__tests__/wait-for.js b/src/__tests__/wait-for.js
index f4cf0a6c..0c1db336 100644
--- a/src/__tests__/wait-for.js
+++ b/src/__tests__/wait-for.js
@@ -32,3 +32,9 @@ test('uses generic error if there was no last error', async () => {
   ).catch(e => e)
   expect(result).toMatchInlineSnapshot(`[Error: Timed out in waitFor.]`)
 })
+
+test('throws nice error if provided callback is not a function', () => {
+  expect(() => waitFor('not a function')).toThrow(
+    'Received `callback` arg must be a function',
+  )
+})
diff --git a/src/wait-for.js b/src/wait-for.js
index 376594d5..9055113b 100644
--- a/src/wait-for.js
+++ b/src/wait-for.js
@@ -22,6 +22,10 @@ function waitFor(
     },
   } = {},
 ) {
+  if (typeof callback !== 'function') {
+    throw new Error('Received `callback` arg must be a function')
+  }
+
   // created here so we get a nice stacktrace
   const timedOutError = new Error('Timed out in waitFor.')
   if (interval < 1) interval = 1

From 05aa661570720b5c9fffc486564b0b9fce490ab9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mario=20Beltra=CC=81n=20Alarco=CC=81n?= <belco90@gmail.com>
Date: Tue, 31 Mar 2020 12:10:05 +0200
Subject: [PATCH 2/2] refactor: address pr feedback

---
 src/__tests__/wait-for.js | 7 ++++++-
 src/wait-for.js           | 2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/__tests__/wait-for.js b/src/__tests__/wait-for.js
index 0c1db336..4ba4702d 100644
--- a/src/__tests__/wait-for.js
+++ b/src/__tests__/wait-for.js
@@ -1,3 +1,4 @@
+import {renderIntoDocument} from './helpers/test-utils'
 import {waitFor} from '../'
 
 test('waits callback to not throw an error', async () => {
@@ -34,7 +35,11 @@ test('uses generic error if there was no last error', async () => {
 })
 
 test('throws nice error if provided callback is not a function', () => {
-  expect(() => waitFor('not a function')).toThrow(
+  const {queryByTestId} = renderIntoDocument(`
+    <div data-testid="div"></div>
+  `)
+  const someElement = queryByTestId('div')
+  expect(() => waitFor(someElement)).toThrow(
     'Received `callback` arg must be a function',
   )
 })
diff --git a/src/wait-for.js b/src/wait-for.js
index 9055113b..a7a35f68 100644
--- a/src/wait-for.js
+++ b/src/wait-for.js
@@ -23,7 +23,7 @@ function waitFor(
   } = {},
 ) {
   if (typeof callback !== 'function') {
-    throw new Error('Received `callback` arg must be a function')
+    throw new TypeError('Received `callback` arg must be a function')
   }
 
   // created here so we get a nice stacktrace