fix: properly reprint resolver errors in watch mode

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### Fixes
 
 - `[jest-runner]` Force parallel runs for watch mode, to avoid TTY freeze ([#6647](https://github.com/facebook/jest/pull/6647))
+- `[jest-cli]` properly reprint resolver errors in watch mode ([#6407](https://github.com/facebook/jest/pull/6407))
 
 ## 23.3.0
 

e2e/__tests__/__snapshots__/module_name_mapper.test.js.snap

@@ -13,14 +13,27 @@ exports[`moduleNameMapper wrong configuration 1`] = `
 
     Configuration error:
 
-    Could not locate module ./style.css (mapped as no-such-module)
-
-    Please check:
-
-    \\"moduleNameMapper\\": {
-      \\"/\\\\.(css|less)$/\\": \\"no-such-module\\"
-    },
-    \\"resolver\\": null
+    Could not locate module ./style.css mapped as:
+    no-such-module.
+
+    Please check your configuration for these entries:
+    {
+      \\"moduleNameMapper\\": {
+        \\"/\\\\.(css|less)$/\\": \\"no-such-module\\"
+      },
+      \\"resolver\\": null
+    }
+
+       8 | 'use strict';
+       9 | 
+    > 10 | require('./style.css');
+         | ^
+      11 | 
+      12 | module.exports = () => 'test';
+      13 | 
+
+      at packages/jest-resolve/build/index.js:400:17
+      at index.js:10:1
 
 "
 `;

packages/jest-cli/src/watch.js

@@ -236,7 +236,13 @@ export default function watch(
       outputStream,
       startRun,
       testWatcher,
-    }).catch(error => console.error(chalk.red(error.stack)));
+    }).catch(error =>
+      // Errors thrown inside `runJest`, e.g. by resolvers, are caught here for
+      // continuous watch mode execution. We need to reprint them to the
+      // terminal and give just a little bit of extra space so they fit below
+      // `preRunMessagePrint` message nicely.
+      console.error('\n\n' + chalk.red(error)),
+    );
   };
 
   const onKeypress = (key: string) => {

packages/jest-resolve-dependencies/src/index.js

@@ -100,7 +100,6 @@ class DependencyResolver {
         }
       }
     }
-
     const modules = this._hasteFS.getAllFiles().map(file => ({
       dependencies: this.resolve(file, options),
       file,

packages/jest-resolve/src/index.js

@@ -352,22 +352,13 @@ class Resolver {
               rootDir: this._options.rootDir,
             });
           if (!module) {
-            const error = new Error(
-              chalk.red(`${chalk.bold('Configuration error')}:
-
-Could not locate module ${chalk.bold(moduleName)} (mapped as ${chalk.bold(
-                updatedName,
-              )})
-
-Please check:
-
-"moduleNameMapper": {
-  "${regex.toString()}": "${chalk.bold(mappedModuleName)}"
-},
-"resolver": ${chalk.bold(String(resolver))}`),
+            throw createNoMappedModuleFoundError(
+              moduleName,
+              updatedName,
+              mappedModuleName,
+              regex,
+              resolver,
             );
-            error.stack = '';
-            throw error;
           }
           return module;
         }
@@ -381,4 +372,31 @@ Please check:
   }
 }
 
+const createNoMappedModuleFoundError = (
+  moduleName,
+  updatedName,
+  mappedModuleName,
+  regex,
+  resolver,
+) => {
+  const error = new Error(
+    chalk.red(`${chalk.bold('Configuration error')}:
+
+Could not locate module ${chalk.bold(moduleName)} mapped as:
+${chalk.bold(updatedName)}.
+
+Please check your configuration for these entries:
+{
+  "moduleNameMapper": {
+    "${regex.toString()}": "${chalk.bold(mappedModuleName)}"
+  },
+  "resolver": ${chalk.bold(String(resolver))}
+}`),
+  );
+
+  error.name = '';
+
+  return error;
+};
+
 module.exports = Resolver;