From d5333411c6220e4d9249142956417ed33f2ed6f3 Mon Sep 17 00:00:00 2001
From: David B <babel.david@gmail.com>
Date: Mon, 12 Nov 2018 15:03:29 +0100
Subject: [PATCH 1/2] update only if i'm the touched item

---
 src/FastField.tsx | 28 +++++++++++++++-------------
 src/Formik.tsx    |  4 ++++
 src/types.tsx     |  2 ++
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/src/FastField.tsx b/src/FastField.tsx
index 2f1595c5d..03dcfa774 100644
--- a/src/FastField.tsx
+++ b/src/FastField.tsx
@@ -110,20 +110,22 @@ class FastFieldInner<Values = {}, Props = {}> extends React.Component<
   ) {
     if (this.props.shouldUpdate) {
       return this.props.shouldUpdate(props, this.props);
-    } else if (
-      getIn(this.props.formik.values, this.props.name) !==
-        getIn(props.formik.values, this.props.name) ||
-      getIn(this.props.formik.errors, this.props.name) !==
-        getIn(props.formik.errors, this.props.name) ||
-      getIn(this.props.formik.touched, this.props.name) !==
-        getIn(props.formik.touched, this.props.name) ||
-      Object.keys(this.props).length !== Object.keys(props).length ||
-      this.props.formik.isSubmitting !== props.formik.isSubmitting
-    ) {
-      return true;
-    } else {
-      return false;
     }
+    if (props.formik.lastTouched === this.props.name) {
+      if (
+        this.props.formik.isSubmitting !== props.formik.isSubmitting ||
+        Object.keys(this.props).length !== Object.keys(props).length ||
+        getIn(this.props.formik.values, this.props.name) !==
+          getIn(props.formik.values, this.props.name) ||
+        getIn(this.props.formik.errors, this.props.name) !==
+          getIn(props.formik.errors, this.props.name) ||
+        getIn(this.props.formik.touched, this.props.name) !==
+          getIn(props.formik.touched, this.props.name)
+      ) {
+        return true;
+      }
+    }
+    return false;
   }
 
   componentDidMount() {
diff --git a/src/Formik.tsx b/src/Formik.tsx
index ddcb1b6d8..e5ce080b9 100755
--- a/src/Formik.tsx
+++ b/src/Formik.tsx
@@ -329,6 +329,7 @@ export class Formik<Values = object, ExtraProps = {}> extends React.Component<
           prevState => ({
             ...prevState,
             values: setIn(prevState.values, field!, val),
+            lastTouched: field,
           }),
           () => {
             if (this.props.validateOnChange) {
@@ -454,6 +455,7 @@ export class Formik<Values = object, ExtraProps = {}> extends React.Component<
 
       this.setState(prevState => ({
         touched: setIn(prevState.touched, field, true),
+        lastTouched: field,
       }));
 
       if (this.props.validateOnBlur) {
@@ -482,6 +484,7 @@ export class Formik<Values = object, ExtraProps = {}> extends React.Component<
       prevState => ({
         ...prevState,
         touched: setIn(prevState.touched, field, touched),
+        lastTouched: field,
       }),
       () => {
         if (this.props.validateOnBlur && shouldValidate) {
@@ -509,6 +512,7 @@ export class Formik<Values = object, ExtraProps = {}> extends React.Component<
       isValidating: false,
       errors: {},
       touched: {},
+      lastTouched: undefined,
       error: undefined,
       status: undefined,
       values,
diff --git a/src/types.tsx b/src/types.tsx
index e21c2fa53..5ab72d17d 100644
--- a/src/types.tsx
+++ b/src/types.tsx
@@ -40,6 +40,8 @@ export interface FormikState<Values> {
   errors: FormikErrors<Values>;
   /** map of field names to whether the field has been touched */
   touched: FormikTouched<Values>;
+  /** Name of the field which trigger the last update event */
+  lastTouched?: string;
   /** whether the form is currently validating */
   isValidating: boolean;
   /** whether the form is currently submitting */

From 86dcc6c64d1771c1a7a74bd260a370dd7a6ec762 Mon Sep 17 00:00:00 2001
From: David B <babel.david@gmail.com>
Date: Mon, 12 Nov 2018 15:20:45 +0100
Subject: [PATCH 2/2] refacto condition in fastfields

---
 src/FastField.tsx | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/FastField.tsx b/src/FastField.tsx
index 03dcfa774..9ab0e0d68 100644
--- a/src/FastField.tsx
+++ b/src/FastField.tsx
@@ -111,21 +111,17 @@ class FastFieldInner<Values = {}, Props = {}> extends React.Component<
     if (this.props.shouldUpdate) {
       return this.props.shouldUpdate(props, this.props);
     }
-    if (props.formik.lastTouched === this.props.name) {
-      if (
-        this.props.formik.isSubmitting !== props.formik.isSubmitting ||
+    return (
+      props.formik.lastTouched === this.props.name &&
+      (this.props.formik.isSubmitting !== props.formik.isSubmitting ||
         Object.keys(this.props).length !== Object.keys(props).length ||
         getIn(this.props.formik.values, this.props.name) !==
           getIn(props.formik.values, this.props.name) ||
         getIn(this.props.formik.errors, this.props.name) !==
           getIn(props.formik.errors, this.props.name) ||
         getIn(this.props.formik.touched, this.props.name) !==
-          getIn(props.formik.touched, this.props.name)
-      ) {
-        return true;
-      }
-    }
-    return false;
+          getIn(props.formik.touched, this.props.name))
+    );
   }
 
   componentDidMount() {