feat: rule: no-unused-keys

Author: refirst11

lib/rules/no-unused-keys.js

@@ -0,0 +1,104 @@
+'use strict'
+
+/**
+ * @param {import('eslint').Rule.RuleContext} context
+ * @returns {import('eslint').Filename}
+ */
+function getFilename(context) {
+  return context.getFilename ? context.getFilename() : context.filename
+}
+
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description:
+        'Detect unused object keys if they are not referenced anywhere',
+      recommended: true,
+    },
+    messages: {
+      unusedKey:
+        "The key '{{ key }}' is defined but never referenced anywhere.",
+    },
+  },
+
+  create(context) {
+    const filename = getFilename(context)
+    if (filename.endsWith('.ts')) {
+      return {}
+    }
+    const parserServices = context.parserServices
+    const checker = parserServices?.program?.getTypeChecker()
+    const definedKeys = new Map()
+    const referencedKeys = new Set()
+
+    return {
+      // Filter out `css.global` and find objects in functions
+      CallExpression(node) {
+        if (
+          node.callee.type === 'MemberExpression' &&
+          node.callee.object.name === 'css' &&
+          node.callee.property.name !== 'global' &&
+          node.callee.property.name !== 'defineThemeVars' &&
+          node.callee.property.name !== 'keyframes'
+        ) {
+          const arg = node.arguments[0]
+          if (
+            arg &&
+            arg.type === 'ObjectExpression' &&
+            node.parent.type === 'VariableDeclarator'
+          ) {
+            const variableName = node.parent.id.name
+            const keyMap = new Map()
+
+            arg.properties.forEach((prop) => {
+              if (
+                prop.key &&
+                prop.key.type === 'Identifier' &&
+                prop.value.type === 'ObjectExpression'
+              ) {
+                keyMap.set(prop.key.name, prop.key)
+              }
+            })
+
+            definedKeys.set(variableName, keyMap)
+          }
+        }
+      },
+      // `styles.header_main` の参照を記録
+      MemberExpression(node) {
+        if (
+          node.object.type === 'Identifier' &&
+          node.property.type === 'Identifier'
+        ) {
+          const fullKey = `${node.object.name}.${node.property.name}`
+          referencedKeys.add(fullKey)
+
+          // TypeScript の型情報を取得し、ジャンプ可能かチェック
+          if (parserServices && checker) {
+            const tsNode = parserServices.esTreeNodeToTSNodeMap.get(node)
+            const symbol = checker.getSymbolAtLocation(tsNode)
+            if (symbol) {
+              referencedKeys.add(fullKey)
+            }
+          }
+        }
+      },
+      'Program:exit'() {
+        definedKeys.forEach((keyMap, variableName) => {
+          keyMap.forEach((keyNode, keyName) => {
+            const fullKey = `${variableName}.${keyName}`
+            if (!referencedKeys.has(fullKey)) {
+              context.report({
+                node: keyNode,
+                messageId: 'unusedKey',
+                data: { key: keyName },
+              })
+            }
+          })
+        })
+      },
+    }
+  },
+}