[New] components detection: track React imports

The default React import and named React import specifiers are tracked during a Components.detect rules definition.
Rules using Components.detect can access the default import specifier using `components.getDefaultReactImport()` and an array any named import specifiers using `components.getNamedReactImports()`
Within a rule, these specifier nodes can be checked to ensure identifiers in scope correspond with the imported identifiers.

Not treating this as semver-minor since it's not part of the documented API.

CHANGELOG.md

@@ -8,6 +8,7 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 ### Changed
 * [Refactor] [`no-arrow-function-lifecycle`], [`no-unused-class-component-methods`]: use report/messages convention (@ljharb)
 * [Tests] component detection: Add testing scaffolding ([#3149][] @duncanbeevers)
+* [New] component detection: track React imports ([#3149][] @duncanbeevers)
 
 [#3149]: https://github.com/yannickcr/eslint-plugin-react/pull/3149
 

lib/util/Components.js

@@ -47,13 +47,15 @@ function mergeUsedPropTypes(propsList, newPropsList) {
 }
 
 const Lists = new WeakMap();
+const ReactImports = new WeakMap();
 
 /**
  * Components
  */
 class Components {
   constructor() {
     Lists.set(this, {});
+    ReactImports.set(this, {});
   }
 
   /**
@@ -179,6 +181,52 @@ class Components {
     const list = Lists.get(this);
     return Object.keys(list).filter((i) => list[i].confidence >= 2).length;
   }
+
+  /**
+   * Return the node naming the default React import
+   * It can be used to determine the local name of import, even if it's imported
+   * with an unusual name.
+   *
+   * @returns {ASTNode} React default import node
+   */
+  getDefaultReactImports() {
+    return ReactImports.get(this).defaultReactImports;
+  }
+
+  /**
+   * Return the nodes of all React named imports
+   *
+   * @returns {Object} The list of React named imports
+   */
+  getNamedReactImports() {
+    return ReactImports.get(this).namedReactImports;
+  }
+
+  /**
+   * Add the default React import specifier to the scope
+   *
+   * @param {ASTNode} specifier The AST Node of the default React import
+   * @returns {void}
+   */
+  addDefaultReactImport(specifier) {
+    const info = ReactImports.get(this);
+    ReactImports.set(this, Object.assign({}, info, {
+      defaultReactImports: (info.defaultReactImports || []).concat(specifier),
+    }));
+  }
+
+  /**
+   * Add a named React import specifier to the scope
+   *
+   * @param {ASTNode} specifier The AST Node of a named React import
+   * @returns {void}
+   */
+  addNamedReactImport(specifier) {
+    const info = ReactImports.get(this);
+    ReactImports.set(this, Object.assign({}, info, {
+      namedReactImports: (info.namedReactImports || []).concat(specifier),
+    }));
+  }
 }
 
 function getWrapperFunctions(context, pragma) {
@@ -857,6 +905,25 @@ function componentRule(rule, context) {
     },
   };
 
+  // Detect React import specifiers
+  const reactImportInstructions = {
+    ImportDeclaration(node) {
+      const isReactImported = node.source.type === 'Literal' && node.source.value === 'react';
+      if (!isReactImported) {
+        return;
+      }
+
+      node.specifiers.forEach((specifier) => {
+        if (specifier.type === 'ImportDefaultSpecifier') {
+          components.addDefaultReactImport(specifier);
+        }
+        if (specifier.type === 'ImportSpecifier') {
+          components.addNamedReactImport(specifier);
+        }
+      });
+    },
+  };
+
   // Update the provided rule instructions to add the component detection
   const ruleInstructions = rule(context, components, utils);
   const updatedRuleInstructions = Object.assign({}, ruleInstructions);
@@ -866,7 +933,8 @@ function componentRule(rule, context) {
   const allKeys = new Set(Object.keys(detectionInstructions).concat(
     Object.keys(propTypesInstructions),
     Object.keys(usedPropTypesInstructions),
-    Object.keys(defaultPropsInstructions)
+    Object.keys(defaultPropsInstructions),
+    Object.keys(reactImportInstructions)
   ));
 
   allKeys.forEach((instruction) => {
@@ -883,6 +951,9 @@ function componentRule(rule, context) {
       if (instruction in defaultPropsInstructions) {
         defaultPropsInstructions[instruction](node);
       }
+      if (instruction in reactImportInstructions) {
+        reactImportInstructions[instruction](node);
+      }
       if (ruleInstructions[instruction]) {
         return ruleInstructions[instruction](node);
       }

tests/util/Component.js

@@ -76,5 +76,23 @@ describe('Components', () => {
         });
       });
     });
+
+    it('should detect React Imports', () => {
+      testComponentsDetect({
+        code: 'import React, { useCallback, useState } from \'react\'',
+      }, (_context, components) => {
+        assert.deepEqual(
+          components.getDefaultReactImports().map((specifier) => specifier.local.name),
+          ['React'],
+          'default React import identifier should be "React"'
+        );
+
+        assert.deepEqual(
+          components.getNamedReactImports().map((specifier) => specifier.local.name),
+          ['useCallback', 'useState'],
+          'named React import identifiers should be "useCallback" and "useState"'
+        );
+      });
+    });
   });
 });