diff --git a/src/useConstant.js b/src/useConstant.js
deleted file mode 100644
index 929be24..0000000
--- a/src/useConstant.js
+++ /dev/null
@@ -1,22 +0,0 @@
-// @flow
-import React from 'react'
-
-/**
- * A simple hook to create a constant value that lives for
- * the lifetime of the component.
- *
- * Plagiarized from https://github.com/Andarist/use-constant
- *
- * Do NOT reuse this code unless you know what you're doing.
- * Use Andarist's hook; it's more fault tolerant to things like
- * falsy values.
- *
- * @param {Function} init - A function to generate the value
- */
-export default function useConstant<t>(init: () => T): T {
- const ref = React.useRef<?t>()
- if (!ref.current) {
- ref.current = init()
- }
- return ref.current
-}
diff --git a/src/useFieldArray.js b/src/useFieldArray.js
index 6cf256a..b03504b 100644
--- a/src/useFieldArray.js
+++ b/src/useFieldArray.js
@@ -1,12 +1,11 @@
 // @flow
-import { useMemo } from 'react';
+import { useCallback, useMemo } from 'react'
 import { useForm, useField } from 'react-final-form'
 import { fieldSubscriptionItems, ARRAY_ERROR } from 'final-form'
 import type { Mutators } from 'final-form-arrays'
 import type { FieldValidator, FieldSubscription } from 'final-form'
 import type { FieldArrayRenderProps, UseFieldArrayConfig } from './types'
 import defaultIsEqual from './defaultIsEqual'
-import useConstant from './useConstant'
 
 const all: FieldSubscription = fieldSubscriptionItems.reduce((result, key) => {
 result[key] = true
@@ -40,8 +39,8 @@ const useFieldArray = (
 }, {}
 ), [name, formMutators])
 
- const validate: FieldValidator = useConstant(
- () => (value, allValues, meta) => {
+ const validate: FieldValidator = useCallback(
+ (value, allValues, meta) => {
 if (!validateProp) return undefined
 const error = validateProp(value, allValues, meta)
 if (!error &#124;&#124; Array.isArray(error)) {
@@ -52,7 +51,8 @@ const useFieldArray = (
 ;((arrayError: any): Object)[ARRAY_ERROR] = error
 return arrayError
 }
- }
+ },
+ [validateProp]
 )
 
 const {
</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://github.com/final-form/react-final-form-arrays/compare/master...m1ke-t:react-final-form-arrays:master.diff">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="https://github.com/final-form/react-final-form-arrays/compare/master...m1ke-t:react-final-form-arrays:master.diff" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast" selected="selected">配色反転</option>
<option value="larger-text">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>