feat(macro): Error message on wrong usage of macro (#40)

* Added error message for wrong usage of macro

* Print AST node type to console on error.

* Fixed bug with JSXClosingElement

* Remove console.log on jsx, sorry

* Added contributor maurobringolf

* Added testcase for error with wrong node types

* Update .all-contributorsrc

.all-contributorsrc

@@ -93,6 +93,16 @@
       "avatar_url": "https://avatars0.githubusercontent.com/u/9248479?v=4",
       "profile": "http://bekrin.me",
       "contributions": []
+    },
+    {
+      "login": "maurobringolf",
+      "name": "Mauro Bringolf",
+      "avatar_url": "https://avatars0.githubusercontent.com/u/18613301?v=4",
+      "profile": "https://maurobringolf.ch",
+      "contributions": [
+        "code",
+        "test"
+      ]
     }
   ]
 }

README.md

@@ -12,7 +12,7 @@ Pre-evaluate code at build-time
 [![downloads][downloads-badge]][npm-stat]
 [![MIT License][license-badge]][LICENSE]
 
-[![All Contributors](https://img.shields.io/badge/all_contributors-9-orange.svg?style=flat-square)](#contributors)
+[![All Contributors](https://img.shields.io/badge/all_contributors-10-orange.svg?style=flat-square)](#contributors)
 [![PRs Welcome][prs-badge]][prs]
 [![Donate][donate-badge]][donate]
 [![Code of Conduct][coc-badge]][coc]
@@ -341,7 +341,7 @@ Thanks goes to these people ([emoji key][emojis]):
 <!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
 | [<img src="https://avatars.githubusercontent.com/u/1500684?v=3" width="100px;"/><br /><sub>Kent C. Dodds</sub>](https://kentcdodds.com)<br />[💻](https://github.com/kentcdodds/babel-plugin-preval/commits?author=kentcdodds "Code") [📖](https://github.com/kentcdodds/babel-plugin-preval/commits?author=kentcdodds "Documentation") [🚇](#infra-kentcdodds "Infrastructure (Hosting, Build-Tools, etc)") [⚠️](https://github.com/kentcdodds/babel-plugin-preval/commits?author=kentcdodds "Tests") | [<img src="https://avatars3.githubusercontent.com/u/5610087?v=3" width="100px;"/><br /><sub>Matt Phillips</sub>](http://mattphillips.io)<br />[💻](https://github.com/kentcdodds/babel-plugin-preval/commits?author=mattphillips "Code") [📖](https://github.com/kentcdodds/babel-plugin-preval/commits?author=mattphillips "Documentation") [⚠️](https://github.com/kentcdodds/babel-plugin-preval/commits?author=mattphillips "Tests") | [<img src="https://avatars1.githubusercontent.com/u/28024000?v=3" width="100px;"/><br /><sub>Philip Oliver</sub>](https://twitter.com/philipodev)<br />[🐛](https://github.com/kentcdodds/babel-plugin-preval/issues?q=author%3Aphilipodev "Bug reports") | [<img src="https://avatars2.githubusercontent.com/u/2109702?v=3" width="100px;"/><br /><sub>Sorin Davidoi</sub>](https://toot.cafe/@sorin)<br />[🐛](https://github.com/kentcdodds/babel-plugin-preval/issues?q=author%3Asorin-davidoi "Bug reports") [💻](https://github.com/kentcdodds/babel-plugin-preval/commits?author=sorin-davidoi "Code") [⚠️](https://github.com/kentcdodds/babel-plugin-preval/commits?author=sorin-davidoi "Tests") | [<img src="https://avatars4.githubusercontent.com/u/1127238?v=4" width="100px;"/><br /><sub>Luke Herrington</sub>](https://github.com/infiniteluke)<br />[💡](#example-infiniteluke "Examples") | [<img src="https://avatars4.githubusercontent.com/u/22868432?v=4" width="100px;"/><br /><sub>Lufty Wiranda</sub>](http://instagram.com/luftywiranda13)<br />[💻](https://github.com/kentcdodds/babel-plugin-preval/commits?author=luftywiranda13 "Code") | [<img src="https://avatars0.githubusercontent.com/u/3877773?v=4" width="100px;"/><br /><sub>Oscar</sub>](http://obartra.github.io)<br />[💻](https://github.com/kentcdodds/babel-plugin-preval/commits?author=obartra "Code") [⚠️](https://github.com/kentcdodds/babel-plugin-preval/commits?author=obartra "Tests") |
 | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
-| [<img src="https://avatars1.githubusercontent.com/u/14310216?v=4" width="100px;"/><br /><sub>pro-nasa</sub>](https://github.com/pro-nasa)<br />[📖](https://github.com/kentcdodds/babel-plugin-preval/commits?author=pro-nasa "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/9248479?v=4" width="100px;"/><br /><sub>Sergey Bekrin</sub>](http://bekrin.me)<br /> |
+| [<img src="https://avatars1.githubusercontent.com/u/14310216?v=4" width="100px;"/><br /><sub>pro-nasa</sub>](https://github.com/pro-nasa)<br />[📖](https://github.com/kentcdodds/babel-plugin-preval/commits?author=pro-nasa "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/9248479?v=4" width="100px;"/><br /><sub>Sergey Bekrin</sub>](http://bekrin.me)<br /> | [<img src="https://avatars0.githubusercontent.com/u/18613301?v=4" width="100px;"/><br /><sub>Mauro Bringolf</sub>](https://maurobringolf.ch)<br /> |
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 
 This project follows the [all-contributors][all-contributors] specification.

src/__tests__/__snapshots__/macros.js.snap

@@ -44,3 +44,15 @@ const x = preval\`module.exports = require('./fixtures/compute-one')\`
 const x = 1;
 
 `;
+
+exports[`error for other nodes 1`] = `
+
+const preval = require('../macro')
+
+x = 3 + preval
+
+      ↓ ↓ ↓ ↓ ↓ ↓
+
+Error: <PROJECT_ROOT>/src/__tests__/macros.js: ../macro: babel-plugin-preval/macro can only be used as tagged template expression, function call or JSX element. You tried BinaryExpression.
+
+`;

src/__tests__/macros.js

@@ -48,6 +48,15 @@ pluginTester({
         )
       `,
     },
+    {
+      title: 'error for other nodes',
+      error: true,
+      code: `
+        const preval = require('../macro')
+
+        x = 3 + preval
+      `,
+    },
   ]),
 })
 

src/macro.js

@@ -19,8 +19,13 @@ function prevalMacros({references, state}) {
         },
         state,
       )
+    } else if (referencePath.parentPath.type === 'JSXClosingElement') {
+      // That's okay, we already prevaled this one on its opening element.
     } else {
-      // TODO: throw a helpful error message
+      throw new Error(
+        `babel-plugin-preval/macro can only be used as tagged template expression, function call or JSX element. You tried ${referencePath
+          .parentPath.type}.`,
+      )
     }
   })
 }