Update vue/no-unused-properties and vue/script-setup-uses-vars rule to support style CSS vars

Author: ota-meshi

lib/rules/no-unused-properties.js

@@ -10,6 +10,7 @@
 
 const utils = require('../utils')
 const eslintUtils = require('eslint-utils')
+const { getStyleVariablesContext } = require('../utils/style-variables')
 
 /**
  * @typedef {import('../utils').GroupName} GroupName
@@ -1044,6 +1045,15 @@ module.exports = {
       {
         /** @param {Program} node */
         'Program:exit'(node) {
+          const styleVars = getStyleVariablesContext(context)
+          if (styleVars) {
+            for (const { id } of styleVars.references) {
+              templatePropertiesContainer.usedProperties.addUsed(
+                id.name,
+                (context) => extractPatternOrThisProperties(id, context, true)
+              )
+            }
+          }
           if (!node.templateBody) {
             reportUnusedProperties()
           }

lib/rules/script-setup-uses-vars.js

@@ -4,6 +4,7 @@
  */
 'use strict'
 
+const { getStyleVariablesContext } = require('../utils/style-variables')
 // ------------------------------------------------------------------------------
 // Requirements
 // ------------------------------------------------------------------------------
@@ -112,7 +113,16 @@ module.exports = {
           }
         }
       },
-      undefined,
+      {
+        Program() {
+          const styleVars = getStyleVariablesContext(context)
+          if (styleVars) {
+            for (const ref of styleVars.references) {
+              context.markVariableAsUsed(ref.id.name)
+            }
+          }
+        }
+      },
       {
         templateBodyTriggerSelector: 'Program'
       }

lib/utils/style-variables/index.js

@@ -0,0 +1,58 @@
+const { isVElement } = require('..')
+
+module.exports = {
+  getStyleVariablesContext
+}
+
+class StyleVariablesContext {
+  /**
+   * @param {RuleContext} context
+   * @param {VElement[]} styles
+   */
+  constructor(context, styles) {
+    this.context = context
+    this.styles = styles
+    /** @type {VReference[]} */
+    this.references = []
+    for (const style of styles) {
+      for (const node of style.children) {
+        if (node.type === 'VExpressionContainer') {
+          for (const ref of node.references.filter(
+            (ref) => ref.variable == null
+          )) {
+            this.references.push(ref)
+          }
+        }
+      }
+    }
+  }
+}
+
+/** @type {Map<VElement, StyleVariablesContext} */
+const cache = new Map()
+/**
+ * Get the style vars context
+ * @param {RuleContext} context
+ * @returns {StyleVariablesContext | null}
+ */
+function getStyleVariablesContext(context) {
+  const df =
+    context.parserServices.getDocumentFragment &&
+    context.parserServices.getDocumentFragment()
+  if (!df) {
+    return null
+  }
+  const styles = df.children
+    .filter(isVElement)
+    .filter((e) => e.name === 'style')
+  if (!styles.length) {
+    return null
+  }
+  let ctx = cache.get(styles[0])
+  if (ctx) {
+    return ctx
+  }
+  ctx = new StyleVariablesContext(context, styles)
+  cache.set(styles[0], ctx)
+  return ctx
+}

tests/lib/rules/no-unused-properties.js

@@ -1535,6 +1535,38 @@ tester.run('no-unused-properties', rule, {
           ignorePublicMembers: true
         }
       ]
+    },
+
+    //style vars
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <div class="text">hello</div>
+        </template>
+
+        <script>
+          export default {
+            data() {
+              return {
+                color: 'red',
+                font: {
+                  size: '2em',
+                },
+              }
+            },
+          }
+        </script>
+
+        <style>
+          .text {
+            color: v-bind(color);
+
+            /* expressions (wrap in quotes) */
+            font-size: v-bind('font.size');
+          }
+        </style>
+        `
     }
   ],
 

tests/lib/rules/script-setup-uses-vars.js

@@ -179,6 +179,25 @@ describe('script-setup-uses-vars', () => {
           <div ref="v"/>
         </template>
         `
+      },
+
+      //style vars
+      {
+        filename: 'test.vue',
+        code: `
+        <script setup>
+          /* eslint script-setup-uses-vars: 1 */
+          const color = 'red'
+          const font = { size: '2em' }
+        </script>
+
+        <style>
+          * {
+            color: v-bind(color);
+            font-size: v-bind('font.size');
+          }
+        </style>
+        `
       }
     ],
 
@@ -305,6 +324,27 @@ describe('script-setup-uses-vars', () => {
             line: 4
           }
         ]
+      },
+
+      //style vars
+      {
+        filename: 'test.vue',
+        code: `
+        <script setup>
+          /* eslint script-setup-uses-vars: 1 */
+          const color = 'red'
+        </script>
+
+        <style>
+          .v-bind .color {
+            color: 'v-bind(color)';
+            background-color: 'v-bind(color)';
+          }
+          /* v-bind(color) */
+          // v-bind(color)
+        </style>
+        `,
+        errors: ["'color' is assigned a value but never used."]
       }
     ]
   })