Fix bug: duplicate "h"

index.js

@@ -63,6 +63,22 @@ module.exports = function (babel) {
             if (isInsideJsxExpression(t, path)) {
               return
             }
+            // do nothing if there is a `const h = ...` already
+            const duplicateHChecker = {
+              hasH: false
+            }
+            path.traverse({
+              Declaration (path) {
+                const container = path.container[0]
+                if (['const', 'let'].includes(container.kind) && container.declarations[0].id.name === 'h') {
+                  console.warn('Duplicate declaration "h" detected. Plugin will not inject h.')
+                  this.hasH = true
+                }
+              }
+            }, duplicateHChecker)
+            if (duplicateHChecker.hasH) {
+              return
+            }
             const isRender = path.node.key.name === 'render'
             // inject h otherwise
             path.get('body').unshiftContainer('body', t.variableDeclaration('const', [

test/test.js

@@ -235,6 +235,60 @@ describe('babel-plugin-transform-vue-jsx', () => {
     expect(nested.children[0].text).to.equal('bar')
   })
 
+  it('duplicate h from this should be skipped', () => {
+    const fun = (obj) => {
+      const vnode = render(h => obj.rende.call({ $createElement: h }))
+      expect(vnode.tag).to.equal('div')
+      expect(vnode.children[0].text).to.equal('test')
+    }
+
+    const exported = {
+      methods: {
+        callFun () {
+          fun({
+            testProp: 1,
+            rende () {
+              /* eslint-disable no-unused-vars */
+              const h = this.$createElement
+              return (
+                <div>test</div>
+              )
+            }
+          })
+        }
+      }
+    }
+
+    exported.methods.callFun()
+  })
+
+  it('duplicate h from arguments should be skipped', () => {
+    const fun = (obj) => {
+      const vnode = render(h => obj.rende.call({ $createElement: () => {
+        throw new Error('this.$createElement should not be called at this time.')
+      } }, h))
+      expect(vnode.tag).to.equal('div')
+      expect(vnode.children[0].text).to.equal('test')
+    }
+
+    const exported = {
+      methods: {
+        callFun () {
+          fun({
+            testProp: 1,
+            rende (h) {
+              return (
+                <div>test</div>
+              )
+            }
+          })
+        }
+      }
+    }
+
+    exported.methods.callFun()
+  })
+
   it('h injection in object getters', () => {
     const obj = {
       get computed () {