[New] display-name: add checkContextObjects option

JulesBlm · ljharb · commit a684ae152ccd · 2023-02-09T21:26:18.000+01:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,10 +5,14 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 
 ## Unreleased
 
+### Added
+* [`display-name`]: add `checkContextObjects` option ([#3529][] @JulesBlm)
+
 ### Fixed
 * [`no-array-index-key`]: consider flatMap ([#3530][] @k-yle)
 
 [#3530]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3530
+[#3529]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3529
 
 ## [7.32.2] - 2023.01.28
 
diff --git a/docs/rules/display-name.md b/docs/rules/display-name.md
@@ -45,7 +45,7 @@ const Hello = React.memo(function Hello({ a }) {
 
 ```js
 ...
-"react/display-name": [<enabled>, { "ignoreTranspilerName": <boolean> }]
+"react/display-name": [<enabled>, { "ignoreTranspilerName": <boolean>, "checkContextObjects": <boolean> }]
 ...
 ```
 
@@ -128,6 +128,33 @@ function HelloComponent() {
 module.exports = HelloComponent();
 ```
 
+### checkContextObjects (default: `false`)
+
+`displayName` allows you to [name your context](https://reactjs.org/docs/context.html#contextdisplayname) object. This name is used in the React dev tools for the context's `Provider` and `Consumer`.
+When `true` this rule will warn on context objects without a `displayName`.
+
+Examples of **incorrect** code for this rule:
+
+```jsx
+const Hello = React.createContext();
+```
+
+```jsx
+const Hello = createContext();
+```
+
+Examples of **correct** code for this rule:
+
+```jsx
+const Hello = React.createContext();
+Hello.displayName = "HelloContext";
+```
+
+```jsx
+const Hello = createContext();
+Hello.displayName = "HelloContext";
+```
+
 ## About component detection
 
 For this rule to work we need to detect React components, this could be very hard since components could be declared in a lot of ways.
diff --git a/lib/rules/display-name.js b/lib/rules/display-name.js
@@ -8,6 +8,7 @@
 const values = require('object.values');
 
 const Components = require('../util/Components');
+const isCreateContext = require('../util/isCreateContext');
 const astUtil = require('../util/ast');
 const componentUtil = require('../util/componentUtil');
 const docsUrl = require('../util/docsUrl');
@@ -21,6 +22,7 @@ const report = require('../util/report');
 
 const messages = {
   noDisplayName: 'Component definition is missing display name',
+  noContextDisplayName: 'Context definition is missing display name',
 };
 
 module.exports = {
@@ -40,6 +42,9 @@ module.exports = {
         ignoreTranspilerName: {
           type: 'boolean',
         },
+        checkContextObjects: {
+          type: 'boolean',
+        },
       },
       additionalProperties: false,
     }],
@@ -48,6 +53,9 @@ module.exports = {
   create: Components.detect((context, components, utils) => {
     const config = context.options[0] || {};
     const ignoreTranspilerName = config.ignoreTranspilerName || false;
+    const checkContextObjects = (config.checkContextObjects || false) && testReactVersion(context, '>= 16.3.0');
+
+    const contextObjects = new Map();
 
     /**
      * Mark a prop type as declared
@@ -87,6 +95,16 @@ module.exports = {
       });
     }
 
+    /**
+     * Reports missing display name for a given context object
+     * @param {Object} contextObj The context object to process
+     */
+    function reportMissingContextDisplayName(contextObj) {
+      report(context, messages.noContextDisplayName, 'noContextDisplayName', {
+        node: contextObj.node,
+      });
+    }
+
     /**
      * Checks if the component have a name set by the transpiler
      * @param {ASTNode} node The AST node being checked.
@@ -144,6 +162,16 @@ module.exports = {
     // --------------------------------------------------------------------------
 
     return {
+      ExpressionStatement(node) {
+        if (checkContextObjects && isCreateContext(node)) {
+          contextObjects.set(node.expression.left.name, { node, hasDisplayName: false });
+        }
+      },
+      VariableDeclarator(node) {
+        if (checkContextObjects && isCreateContext(node)) {
+          contextObjects.set(node.id.name, { node, hasDisplayName: false });
+        }
+      },
       'ClassProperty, PropertyDefinition'(node) {
         if (!propsUtil.isDisplayNameDeclaration(node)) {
           return;
@@ -155,6 +183,14 @@ module.exports = {
         if (!propsUtil.isDisplayNameDeclaration(node.property)) {
           return;
         }
+        if (
+          checkContextObjects
+          && node.object
+          && node.object.name
+          && contextObjects.has(node.object.name)
+        ) {
+          contextObjects.get(node.object.name).hasDisplayName = true;
+        }
         const component = utils.getRelatedComponent(node);
         if (!component) {
           return;
@@ -258,6 +294,11 @@ module.exports = {
         values(list).filter((component) => !component.hasDisplayName).forEach((component) => {
           reportMissingDisplayName(component);
         });
+        if (checkContextObjects) {
+          // Report missing display name for all context objects
+          const contextsList = Array.from(contextObjects.values()).filter((v) => !v.hasDisplayName);
+          contextsList.forEach((contextObj) => reportMissingContextDisplayName(contextObj));
+        }
       },
     };
   }),
diff --git a/lib/util/isCreateContext.js b/lib/util/isCreateContext.js
@@ -0,0 +1,53 @@
+'use strict';
+
+/**
+ * Checks if the node is a React.createContext call
+ * @param {ASTNode} node - The AST node being checked.
+ * @returns {Boolean} - True if node is a React.createContext call, false if not.
+ */
+module.exports = function isCreateContext(node) {
+  if (
+    node.init
+    && node.init.type === 'CallExpression'
+    && node.init.callee
+    && node.init.callee.name === 'createContext'
+  ) {
+    return true;
+  }
+
+  if (
+    node.init
+    && node.init.callee
+    && node.init.callee.type === 'MemberExpression'
+    && node.init.callee.property
+    && node.init.callee.property.name === 'createContext'
+  ) {
+    return true;
+  }
+
+  if (
+    node.expression
+    && node.expression.type === 'AssignmentExpression'
+    && node.expression.operator === '='
+    && node.expression.right.type === 'CallExpression'
+    && node.expression.right.callee
+    && node.expression.right.callee.name === 'createContext'
+  ) {
+    return true;
+  }
+
+  if (
+    node.expression
+    && node.expression.type === 'AssignmentExpression'
+    && node.expression.operator === '='
+    && node.expression.right.type === 'CallExpression'
+    && node.expression.right.callee
+    && node.expression.right.callee.type === 'MemberExpression'
+    && node.expression.right.callee.property
+    && node.expression.right.callee.property.name === 'createContext'
+  ) {
+    return true;
+  }
+
+  return false;
+};
diff --git a/tests/lib/rules/display-name.js b/tests/lib/rules/display-name.js
