Option to generate report file

README.md

@@ -226,6 +226,28 @@ module.exports = {
 }
 ```
 
+##### `outputReport` (default: `false`)
+Write the output of the errors to a file, for example a checkstyle xml file for use for reporting on Jenkins CI
+
+The `filePath` is relative to the webpack config: output.path
+You can pass in a different formatter for the output file, if none is passed in the default/configured formatter will be used
+
+```js
+module.exports = {
+  entry: "...",
+  module: {
+    // ...
+  },
+  eslint: {
+    outputReport: {
+      filePath: 'checkstyle.xml',
+      formatter: require('eslint/lib/formatters/checkstyle')
+    }
+  }
+}
+```
+
+
 ## Gotchas
 
 ### NoErrorsPlugin
@@ -239,5 +261,3 @@ remove `NoErrorsPlugin` from webpack config.
 ## [Changelog](CHANGELOG.md)
 
 ## [License](LICENSE)
-
-

index.js

@@ -84,6 +84,18 @@ function lint(input, config, webpack) {
       })
       var messages = config.formatter(res.results)
 
+      if (config.outputReport) {
+        var reportOutput
+        // if a different formatter is passed in as an option use that
+        if (config.outputReport.formatter) {
+          reportOutput = config.outputReport.formatter(res.results)
+        }
+        else {
+          reportOutput = messages
+        }
+        webpack.emitFile(config.outputReport.filePath, reportOutput)
+      }
+
       // default behavior: emit error only if we have errors
       var emitter = res.errorCount ? webpack.emitError : webpack.emitWarning
 

test/formatter.js

@@ -2,6 +2,7 @@ var test = require("tape")
 var webpack = require("webpack")
 var assign = require("object-assign")
 var conf = require("./utils/conf")
+var fs = require("fs")
 
 /* eslint-disable no-console */
 test("eslint-loader can use eslint formatter", function(t) {
@@ -57,3 +58,51 @@ test("eslint-loader can use custom formatter", function(t) {
     t.end()
   })
 })
+
+test("eslint-loader cant be configured to write eslint results to a file",
+function(t) {
+
+  var outputFilename = "outputReport.txt"
+
+  webpack(assign({},
+    conf,
+    {
+      entry: "./test/fixtures/error.js",
+      eslint: assign({}, conf.eslint, {
+        formatter: require("eslint/lib/formatters/checkstyle"),
+        outputReport: {
+          filePath: outputFilename,
+        },
+      }),
+    }
+  ),
+  function(err, stats) {
+    if (err) {
+      throw err
+    }
+
+    console.log("### Here is a the outpur of the formatter")
+    console.log(
+      "# " +
+      stats.compilation.errors[0].message
+        .split("\n")
+        .join("\n# ")
+    )
+
+    fs.readFile(conf.output.path + outputFilename,
+      "utf8", function(err, contents) {
+        if (err) {
+          t.fail("Expected file to have been created")
+        }
+        else {
+          t.pass("File has been created")
+
+          t.equal(stats.compilation.errors[0].message, contents,
+            "File Contents should equal output")
+        }
+
+      })
+
+    t.end()
+  })
+})