Add sort-styles rule

README.md

@@ -4,7 +4,7 @@ ESLint plugin for React Native
 
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-[![Maintenance Status][status-image]][status-url] [![NPM version][npm-image]][npm-url] [![Build Status][travis-image]][travis-url] [![Dependency Status][deps-image]][deps-url] [![Coverage Status][coverage-image]][coverage-url] [![Code Climate][climate-image]][climate-url] [![BCH compliance][bettercode-image]][bettercode-url] 
+[![Maintenance Status][status-image]][status-url] [![NPM version][npm-image]][npm-url] [![Build Status][travis-image]][travis-url] [![Dependency Status][deps-image]][deps-url] [![Coverage Status][coverage-image]][coverage-url] [![Code Climate][climate-image]][climate-url] [![BCH compliance][bettercode-image]][bettercode-url]
 
 React Native specific linting rules for ESLint. This repository is structured like  (and contains code from) the excellent [eslint-plugin-react](http://github.com/yannickcr/eslint-plugin-react).
 
@@ -79,6 +79,7 @@ Finally, enable all of the rules that you would like to use.
 # List of supported rules
 
 * [no-unused-styles](docs/rules/no-unused-styles.md): Detect `StyleSheet` rules which are not used in your React components
+* [sort-styles](docs/rules/sort-styles.md): Require style definitions to be sorted alphabetically
 * [split-platform-components](docs/rules/split-platform-components.md): Enforce using platform specific filenames when necessary
 * [no-inline-styles](docs/rules/no-inline-styles.md): Detect JSX components with inline styles that contain literal values
 * [no-color-literals](docs/rules/no-color-literals.md): Detect `StyleSheet` rules and inline styles containing color literals instead of variables

docs/rules/sort-styles.md

@@ -0,0 +1,132 @@
+# Require StyleSheet keys to be sorted
+It's like [sort-keys](https://eslint.org/docs/rules/sort-keys), but just for React Native styles.
+
+Keeping your style definitions sorted is a common convention that helps with readability. This rule lets you enforce an ascending (default) or descending alphabetical order for both "class names" and style properties.
+
+## Rule Details
+
+The following patterns are considered warnings:
+
+```js
+const styles = StyleSheet.create({
+  button: {
+    width: 100,
+    color: 'green',
+  },
+});
+```
+
+```js
+const styles = StyleSheet.create({
+  button: {},
+  anchor: {},
+});
+```
+
+The following patterns are not considered warnings:
+
+```js
+const styles = StyleSheet.create({
+  button: {
+    color: 'green',
+    width: 100,
+  },
+});
+```
+
+```js
+const styles = StyleSheet.create({
+  anchor: {},
+  button: {},
+});
+```
+
+## Options
+
+```
+{
+    "react-native/sort-styles": ["error", "asc", { "ignoreClassNames": false, "ignoreStyleProperties": false }]
+}
+```
+
+The 1st option is "asc" or "desc".
+
+* `"asc"` (default) - enforce properties to be in ascending order.
+* `"desc"` - enforce properties to be in descending order.
+
+The 2nd option is an object which has 2 properties.
+
+* `ignoreClassNames` - if `true`, order will not be enforced on the class name level. Default is `false`.
+* `ignoreStyleProperties` - if `true`, order will not be enforced on the style property level. Default is `false`.
+
+### desc
+
+`/* eslint react-native/sort-styles: ["error", "desc"] */`
+
+The following patterns are considered warnings:
+
+```js
+const styles = StyleSheet.create({
+  button: {
+    color: 'green',
+    width: 100,
+  },
+});
+```
+
+```js
+const styles = StyleSheet.create({
+  anchor: {},
+  button: {},
+});
+```
+
+The following patterns are not considered warnings:
+
+```js
+const styles = StyleSheet.create({
+  button: {
+    width: 100,
+    color: 'green',
+  },
+});
+```
+
+```js
+const styles = StyleSheet.create({
+  button: {},
+  anchor: {},
+});
+```
+
+### ignoreClassNames
+
+`/* eslint react-native/sort-styles: ["error", "asc", { "ignoreClassNames": true }] */`
+
+The following patterns are not considered warnings:
+
+```js
+const styles = StyleSheet.create({
+  button: {
+    color: 'green',
+    width: 100,
+  },
+  anchor: {},
+});
+```
+
+# ignoreStyleProperties
+
+`/* eslint react-native/sort-styles: ["error", "asc", { "ignoreStyleProperties": true }] */`
+
+The following patterns are not considered warnings:
+
+```js
+const styles = StyleSheet.create({
+  anchor: {},
+  button: {
+    width: 100,
+    color: 'green',
+  },
+});
+```

index.js

@@ -6,6 +6,7 @@ const allRules = {
   'no-unused-styles': require('./lib/rules/no-unused-styles'),
   'no-inline-styles': require('./lib/rules/no-inline-styles'),
   'no-color-literals': require('./lib/rules/no-color-literals'),
+  'sort-styles': require('./lib/rules/sort-styles'),
   'split-platform-components': require('./lib/rules/split-platform-components'),
   'no-raw-text': require('./lib/rules/no-raw-text'),
 };
@@ -30,6 +31,7 @@ module.exports = {
     'no-unused-styles': 0,
     'no-inline-styles': 0,
     'no-color-literals': 0,
+    'sort-styles': 0,
     'split-platform-components': 0,
     'no-raw-text': 0,
   },

lib/rules/sort-styles.js

@@ -0,0 +1,94 @@
+/**
+ * @fileoverview Rule to require StyleSheet object keys to be sorted
+ * @author Mats Byrkjeland
+ */
+
+'use strict';
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const { astHelpers } = require('../util/stylesheet');
+
+const { getStyleDeclarations, isStyleSheetDeclaration } = astHelpers;
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = (context) => {
+  const order = context.options[0] || 'asc';
+  const options = context.options[1] || {};
+  const ignoreClassNames = options.ignoreClassNames;
+  const ignoreStyleProperties = options.ignoreStyleProperties;
+  const isValidOrder = order === 'asc' ? (a, b) => a <= b : (a, b) => a >= b;
+
+  function report(type, node, prev, current) {
+    const currentName = current.key.name;
+    const prevName = prev.key.name;
+    context.report({
+      node,
+      message: `Expected ${type} to be in ${order}ending order. '${currentName}' should be before '${prevName}'.`,
+      loc: current.key.loc,
+    });
+  }
+
+  function checkIsSorted(array, arrayName, node) {
+    for (let i = 1; i < array.length; i += 1) {
+      const previous = array[i - 1];
+      const current = array[i];
+
+      if (previous.type !== 'Property' || current.type !== 'Property') {
+        return;
+      }
+
+      if (!isValidOrder(previous.key.name, current.key.name)) {
+        return report(arrayName, node, previous, current);
+      }
+    }
+  }
+
+  return {
+    VariableDeclarator: function (node) {
+      if (!isStyleSheetDeclaration(node, context.settings)) {
+        return;
+      }
+
+      const classDefinitions = getStyleDeclarations(node);
+
+      if (!ignoreClassNames) {
+        checkIsSorted(classDefinitions, 'class names', node);
+      }
+
+      if (ignoreStyleProperties) return;
+
+      classDefinitions.forEach((classDefinition) => {
+        const styleProperties = classDefinition.value.properties;
+        if (!styleProperties || styleProperties.length < 2) {
+          return;
+        }
+
+        checkIsSorted(styleProperties, 'style properties', node);
+      });
+    },
+  };
+};
+
+module.exports.schema = [
+  {
+    enum: ['asc', 'desc'],
+  },
+  {
+    type: 'object',
+    properties: {
+      ignoreClassNames: {
+        type: 'boolean',
+      },
+      ignoreStyleProperties: {
+        type: 'boolean',
+      },
+    },
+    additionalProperties: false,
+  },
+];