feat(lib): add cli (#68)

* feat(lib): add CLI

* docs: tune README

Author: jonathanglasmeyer

README.md

@@ -44,15 +44,18 @@ webpack-validator makes it easy:
 ![validation-example](https://cloud.githubusercontent.com/assets/3755413/14134087/b3279738-f654-11e5-9752-367b01ac123d.png)
 
 ### Usage
-In your `webpack.config.js`:
+There are two ways to use webpack-validator: a) "programmatically" by wrapping your webpack config object with a validation function or b) using a command line interface.
+
+For the first approach, add this in your `webpack.config.js`:
 ```js
 const validate = require('webpack-validator')
 
 module.exports = validate({ /* ... your webpack config */ })
 ```
 Now run webpack. Either everything is green and the build continues or `joi` will let you know what's wrong and the build won't continue.
 
-Alternatively just run `node webpack.config.js` to only validate your config and not run webpack.
+#### CLI
+For CLI usage you probably want to install the tool globally (`npm install -g webpack-validator`) first. Then just run `webpack-validator <your-config>`.
 
 #### Customizing
 If you need to extend the schema, for example for custom top level properties or properties added by third party plugins like `eslint-loader` (which adds a toplevel `eslint` property), do it like this:

package.json

@@ -2,6 +2,7 @@
   "name": "webpack-validator",
   "description": "Validate your webpack config with joi",
   "main": "dist",
+  "bin": "./dist/bin/webpack-validator.js",
   "files": [
     "dist"
   ],
@@ -41,8 +42,10 @@
   },
   "dependencies": {
     "chalk": "1.1.3",
+    "commander": "2.9.0",
     "joi": "8.0.5",
-    "lodash": "4.11.1"
+    "lodash": "4.11.1",
+    "npmlog": "2.0.3"
   },
   "devDependencies": {
     "autoprefixer": "6.3.6",

src/bin/webpack-validator.js

@@ -0,0 +1,61 @@
+#!/usr/bin/env node
+
+'use strict'
+const fs = require('fs')
+const path = require('path')
+const program = require('commander')
+const log = require('npmlog')
+const validate = require('../')
+const schema = require('../').schema
+let configFile
+
+program
+  .arguments('<configFileName>')
+  .action((configFileName) => {
+    configFile = configFileName
+  })
+program.parse(process.argv)
+
+function errorHandler(err) {
+  if (err.isJoi && err.name === 'ValidationError' && err.annotate) {
+    log.error(err.annotate())
+  } else {
+    log.error(err.message)
+  }
+  process.exit(1)
+}
+
+function validateConfig(webpackConfigFile) {
+  console.log(`Reading: ${webpackConfigFile}`)
+  const config = require(path.join(process.cwd(), webpackConfigFile))
+  const validationResult = validate(config, schema, { returnValidation: true })
+  if (validationResult.error) {
+    console.info(validationResult.error.annotate())
+    process.exit(1)
+  } else {
+    console.info(`${webpackConfigFile} is valid`)
+    process.exit(0)
+  }
+}
+
+if (! configFile) {
+  const error = new Error(['No configuration file given',
+    'Usage: webpack-validator-cli <configFileName>'].join('\n'))
+  error.type = 'EUSAGE'
+  errorHandler(error)
+}
+
+fs.stat(configFile, (err, stats) => {
+  if (err) {
+    err.message = `Could not find file "${configFile}"` // eslint-disable-line no-param-reassign
+    errorHandler(err)
+  } else {
+    if (stats.isFile()) {
+      validateConfig(configFile)
+    } else {
+      const error = new Error(`Could not find file "${configFile}"`)
+      error.type = 'EISDIR'
+      errorHandler(error)
+    }
+  }
+})