From 31ddfeb4cd7bb3fc35ed90ae6c8b6f70dc02ce3f Mon Sep 17 00:00:00 2001
From: Elvira Burchik <elviraburchik@gmail.com>
Date: Fri, 17 Mar 2023 16:52:16 +0100
Subject: [PATCH] Fix variant breakpoint memoization

---
 src/createRestyleFunction.ts           |  28 ++++++-
 src/test/TestButton.tsx                |  45 +++++++++++
 src/test/TestContainer.tsx             |  68 ++++++++++++++++
 src/test/createRestyleFunction.test.ts |   8 +-
 src/test/useRestyle.test.tsx           | 107 +++++++++++++------------
 5 files changed, 201 insertions(+), 55 deletions(-)
 create mode 100644 src/test/TestButton.tsx
 create mode 100644 src/test/TestContainer.tsx

diff --git a/src/createRestyleFunction.ts b/src/createRestyleFunction.ts
index 980a0282..f9aa441b 100644
--- a/src/createRestyleFunction.ts
+++ b/src/createRestyleFunction.ts
@@ -55,11 +55,37 @@ const createRestyleFunction = <
         typeof themeKey === 'string' &&
         typeof property === 'string'
       ) {
+        /*
+        The following code is required to ensure all variants that have different breakpoint objects are turned into unique strings. By simply retuning String(props[property]), two different variants with breakpoints will return the same string.
+        For example, if we have the following variant:
+          spacingVariant: {
+            defaults: {},
+            noPadding: {
+              phone: 'none',
+              tablet: 'none',
+            },
+            mediumPadding: {
+              phone: 'm',
+              tablet: 'm',
+            }
+          }
+        using String(props[property]) will turn both variants into [object Object], making them equivalent and resulting in separate styles being memoized into the same hash key.
+        By building the propertyValue string ourselves from the breakpoints, we can format the variants to be "phone:nonetablet:none" and "phone:mtablet:m" respectively, making each memoized hash key unique.
+        */
+        let propertyValue = '';
+        if (typeof props[property] === 'object') {
+          for (const [breakpoint, value] of Object.entries(props[property])) {
+            propertyValue += `${breakpoint}:${value}`;
+          }
+        } else {
+          propertyValue = String(props[property]);
+        }
+
         return getMemoizedMapHashKey(
           dimensions,
           String(themeKey),
           String(property),
-          String(props[property]),
+          propertyValue,
         );
       } else {
         return null;
diff --git a/src/test/TestButton.tsx b/src/test/TestButton.tsx
new file mode 100644
index 00000000..dab0005b
--- /dev/null
+++ b/src/test/TestButton.tsx
@@ -0,0 +1,45 @@
+import React, {ComponentPropsWithoutRef} from 'react';
+import {Text, TouchableOpacity} from 'react-native';
+
+import useRestyle from '../hooks/useRestyle';
+import {position, PositionProps} from '../restyleFunctions';
+import createVariant, {VariantProps} from '../createVariant';
+import composeRestyleFunctions from '../composeRestyleFunctions';
+
+const theme = {
+  colors: {},
+  spacing: {},
+  buttonVariants: {
+    defaults: {},
+  },
+  breakpoints: {
+    phone: 0,
+    tablet: 376,
+  },
+  zIndices: {
+    phone: 5,
+  },
+};
+type Theme = typeof theme;
+
+type Props = VariantProps<Theme, 'buttonVariants'> &
+  PositionProps<Theme> &
+  ComponentPropsWithoutRef<typeof TouchableOpacity>;
+
+const restyleFunctions = [
+  position,
+  createVariant<Theme>({themeKey: 'buttonVariants'}),
+];
+
+const composedRestyleFunction = composeRestyleFunctions<Theme, Props>(
+  restyleFunctions,
+);
+
+export function Button({title, ...rest}: Props & {title: string}) {
+  const props = useRestyle(composedRestyleFunction, rest);
+  return (
+    <TouchableOpacity {...props}>
+      <Text>{title}</Text>
+    </TouchableOpacity>
+  );
+}
diff --git a/src/test/TestContainer.tsx b/src/test/TestContainer.tsx
new file mode 100644
index 00000000..958653f0
--- /dev/null
+++ b/src/test/TestContainer.tsx
@@ -0,0 +1,68 @@
+import React from 'react';
+import {View, ViewProps} from 'react-native';
+
+import useRestyle from '../hooks/useRestyle';
+import createVariant, {VariantProps} from '../createVariant';
+import composeRestyleFunctions from '../composeRestyleFunctions';
+import {
+  backgroundColor,
+  BackgroundColorProps,
+  BorderProps,
+  spacing,
+  SpacingProps,
+} from '../restyleFunctions';
+
+const palette = {
+  purple: '#5A31F4',
+  green: '#099C77',
+  black: '#101010',
+  white: '#FFF',
+};
+
+export const theme = {
+  colors: {
+    background: palette.purple,
+  },
+  spacing: {
+    none: 0,
+    m: 8,
+  },
+  breakpoints: {
+    phone: 320,
+    tablet: 768,
+  },
+  spacingVariant: {
+    defaults: {},
+    spacingParent: {
+      padding: {
+        phone: 'none',
+        tablet: 'none',
+      },
+    },
+    spacingNested: {
+      padding: {
+        phone: 'm',
+        tablet: 'm',
+      },
+    },
+  },
+};
+type Theme = typeof theme;
+
+type RestyleProps = SpacingProps<Theme> &
+  BorderProps<Theme> &
+  BackgroundColorProps<Theme> &
+  VariantProps<Theme, 'spacingVariant'>;
+
+const restyleFunctions = composeRestyleFunctions<Theme, RestyleProps>([
+  spacing,
+  backgroundColor,
+  createVariant({themeKey: 'spacingVariant'}),
+]);
+
+type Props = RestyleProps & ViewProps;
+
+export const Container = ({children, ...rest}: Props) => {
+  const props = useRestyle(restyleFunctions, rest);
+  return <View {...props}>{children}</View>;
+};
diff --git a/src/test/createRestyleFunction.test.ts b/src/test/createRestyleFunction.test.ts
index ca168076..33f43d6c 100644
--- a/src/test/createRestyleFunction.test.ts
+++ b/src/test/createRestyleFunction.test.ts
@@ -4,15 +4,15 @@ import {RNStyle} from '../types';
 const theme = {
   colors: {},
   spacing: {},
-  breakpoints: {
-    phone: 0,
-    tablet: 376,
-  },
   opacities: {
     invisible: 0,
     barelyVisible: 0.1,
     almostOpaque: 0.9,
   },
+  breakpoints: {
+    phone: 0,
+    tablet: 376,
+  },
 };
 const dimensions = {
   width: 375,
diff --git a/src/test/useRestyle.test.tsx b/src/test/useRestyle.test.tsx
index bc9523e3..0f2e3149 100644
--- a/src/test/useRestyle.test.tsx
+++ b/src/test/useRestyle.test.tsx
@@ -1,56 +1,63 @@
-import React, {ComponentPropsWithoutRef} from 'react';
-import {Text, TouchableOpacity} from 'react-native';
-
-import useRestyle from '../hooks/useRestyle';
-import {position, PositionProps} from '../restyleFunctions';
-import createVariant, {VariantProps} from '../createVariant';
-import composeRestyleFunctions from '../composeRestyleFunctions';
-
-const theme = {
-  colors: {},
-  spacing: {},
-  buttonVariants: {
-    defaults: {},
-  },
-  breakpoints: {
-    phone: 0,
-    tablet: 376,
-  },
-  zIndices: {
-    phone: 5,
-  },
-};
-type Theme = typeof theme;
-
-type Props = VariantProps<Theme, 'buttonVariants'> &
-  PositionProps<Theme> &
-  ComponentPropsWithoutRef<typeof TouchableOpacity>;
-
-const restyleFunctions = [
-  position,
-  createVariant<Theme>({themeKey: 'buttonVariants'}),
-];
-
-const composedRestyleFunction = composeRestyleFunctions<Theme, Props>(
-  restyleFunctions,
-);
-
-function Button({title, ...rest}: Props & {title: string}) {
-  const props = useRestyle(composedRestyleFunction, rest);
-  return (
-    <TouchableOpacity {...props}>
-      <Text>{title}</Text>
-    </TouchableOpacity>
-  );
-}
-
-function Screen() {
-  return <Button title="test" position="absolute" />;
-}
+import React from 'react';
+import {View} from 'react-native';
+import {create as render} from 'react-test-renderer';
+
+import {ThemeProvider} from '../context';
+
+import {Button} from './TestButton';
+import {Container, theme} from './TestContainer';
 
 describe('Use restyle', () => {
   it('creates a button', () => {
-    const button = Screen();
+    const button = <Button title="test" position="absolute" />;
     expect(button.props.title).toBe('test');
   });
+
+  it('uses theme props', () => {
+    const {root} = render(
+      <ThemeProvider theme={theme}>
+        <Container backgroundColor="background" />
+      </ThemeProvider>,
+    );
+
+    expect(root.findByType(View).props.style).toStrictEqual([
+      {backgroundColor: '#5A31F4'},
+    ]);
+  });
+
+  it('uses theme props with variant', () => {
+    const {root} = render(
+      <ThemeProvider theme={theme}>
+        <Container variant="spacingParent" />
+      </ThemeProvider>,
+    );
+
+    expect(root.findByType(View).props.style).toStrictEqual([{padding: 0}]);
+  });
+
+  it('parent styles match theme', () => {
+    const {root} = render(
+      <ThemeProvider theme={theme}>
+        <Container variant="spacingParent">
+          <Container variant="spacingNested" />
+        </Container>
+      </ThemeProvider>,
+    );
+
+    expect(root.findByType(View).props.style).toStrictEqual([{padding: 0}]);
+  });
+
+  it('child styles match theme', () => {
+    const {root} = render(
+      <ThemeProvider theme={theme}>
+        <Container variant="spacingParent">
+          <Container variant="spacingNested" />
+        </Container>
+      </ThemeProvider>,
+    );
+
+    expect(root.findAllByType(View)[1].props.style).toStrictEqual([
+      {padding: 8},
+    ]);
+  });
 });