fix: emit warning/error if no config was found/given

index.js

@@ -235,6 +235,7 @@ module.exports = function(input, map) {
 
   webpack.cacheable();
 
+  var emitter = config.emitError ? webpack.emitError : webpack.emitWarning;
   var engine = engines[configHash];
   var resourcePath = webpack.resourcePath;
   var cwd = process.cwd();
@@ -255,7 +256,7 @@ module.exports = function(input, map) {
         options: config,
         source: input,
         transform: function() {
-          return lint(engine, input, resourcePath);
+          return lint(engine, input, resourcePath, emitter);
         }
       },
       function(err, res) {
@@ -276,10 +277,20 @@ module.exports = function(input, map) {
       }
     );
   }
-  printLinterOutput(lint(engine, input, resourcePath), config, webpack);
+  printLinterOutput(
+    lint(engine, input, resourcePath, emitter),
+    config,
+    webpack
+  );
   webpack.callback(null, input, map);
 };
 
-function lint(engine, input, resourcePath) {
-  return engine.executeOnText(input, resourcePath, true);
+function lint(engine, input, resourcePath, emitter) {
+  try {
+    return engine.executeOnText(input, resourcePath, true);
+  } catch (_) {
+    if (emitter) emitter(_);
+
+    return { src: input };
+  }
 }

test/no-eslint-configuration.js

@@ -0,0 +1,33 @@
+var test = require("ava");
+var webpack = require("webpack");
+
+var conf = require("./utils/conf");
+
+test.cb(
+  "eslint-loader emit warning when there is no eslint configuration",
+  function(t) {
+    t.plan(2);
+    webpack(
+      conf(
+        {
+          entry: "./test/fixtures/good.js"
+        },
+        {
+          cwd: "/"
+        }
+      ),
+      function(err, stats) {
+        if (err) {
+          throw err;
+        }
+
+        t.true(stats.hasWarnings());
+        t.regex(
+          stats.compilation.warnings[0].message,
+          /no eslint configuration/i
+        );
+        t.end();
+      }
+    );
+  }
+);