fix(no-unused-emit-declarations): detect emits in templates (#2340)

Co-authored-by: Flo Edelmann <[email protected]>

Author: waynzh

lib/rules/no-unused-emit-declarations.js

@@ -56,6 +56,17 @@ function hasReferenceId(value, setupContext) {
   )
 }
 
+/**
+ * Check if the given name matches emitReferenceIds variable name
+ * @param {string} name
+ * @param {Set<Identifier>} emitReferenceIds
+ * @returns {boolean}
+ */
+function isEmitVariableName(name, emitReferenceIds) {
+  const emitVariable = emitReferenceIds.values().next().value.name
+  return emitVariable === name
+}
+
 module.exports = {
   meta: {
     type: 'suggestion',
@@ -191,6 +202,15 @@ module.exports = {
           }
 
           const { contextReferenceIds, emitReferenceIds } = setupContext
+
+          // verify defineEmits variable in template
+          if (
+            callee.type === 'Identifier' &&
+            isEmitVariableName(callee.name, emitReferenceIds)
+          ) {
+            addEmitCall(node)
+          }
+
           // verify setup(props,{emit}) {emit()}
           addEmitCallByReference(callee, emitReferenceIds, node)
           if (emit && emit.name === 'emit') {

tests/lib/rules/no-unused-emit-declarations.js

@@ -98,6 +98,17 @@ tester.run('no-unused-emit-declarations', rule, {
         }
       `
     },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="emits('bar')">Bar</button>
+      </template>
+      <script setup>
+        const emits = defineEmits(['bar'])
+      </script>
+      `
+    },
     {
       filename: 'test.vue',
       code: `
@@ -237,7 +248,7 @@ tester.run('no-unused-emit-declarations', rule, {
         export default {
           emits: ['foo'],
           setup(_, context) {
-            useCustomComposable({ emit: context.emit }) 
+            useCustomComposable({ emit: context.emit })
           }
         }
       </script>
@@ -282,7 +293,7 @@ tester.run('no-unused-emit-declarations', rule, {
         export default {
           emits: ['foo'],
           setup(_, { emit }) {
-            useCustomComposable({ emit: emit }) 
+            useCustomComposable({ emit: emit })
           }
         }
       </script>
@@ -453,6 +464,25 @@ tester.run('no-unused-emit-declarations', rule, {
         }
       ]
     },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="emit('bar')">Bar</button>
+      </template>
+      <script setup>
+        const emit = defineEmits(['foo', 'bar'])
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 6,
+          column: 35,
+          endColumn: 40
+        }
+      ]
+    },
     {
       filename: 'test.vue',
       code: `