suppress unhandled rejections

Author: chrisbreiding

index.js

@@ -148,12 +148,20 @@ const preprocessor = (options = {}) => {
       // we overwrite the latest bundle, so that a new call to this function
       // returns a promise that resolves when the bundling is finished
       latestBundle = createDeferred()
-      bundles[filePath] = latestBundle.promise.tap(() => {
+      bundles[filePath] = latestBundle.promise
+
+      bundles[filePath].tap(() => {
         debug('- compile finished for', filePath)
         // when the bundling is finished, emit 'rerun' to let Cypress
         // know to rerun the spec
         file.emit('rerun')
       })
+      // we suppress unhandled rejections so they don't bubble up to the
+      // unhandledRejection handler and crash the process. Cypress will
+      // eventually take care of the rejection when the file is requested.
+      // note that this does not work if attached to latestBundle.promise
+      // for some reason. it only works when attached after .tap  ¯\_(ツ)_/¯
+      .suppressUnhandledRejections()
     }
 
     // when we should watch, we hook into the 'compile' hook so we know when

test/e2e/e2e_spec.js

@@ -32,4 +32,27 @@ describe('webpack preprocessor - e2e', () => {
       snapshot(fs.readFileSync(outputPath).toString())
     })
   })
+
+  it('allows attaching catch later on syntax error without triggering unhandled rejection', (done) => {
+    process.on('unhandledRejection', (err) => {
+      // eslint-disable-next-line no-console
+      console.error('Unhandled Rejection:', err.stack)
+      done('Should not have trigger unhandled rejection')
+    })
+
+    file.shouldWatch = true
+
+    preprocessor()(file).then(() => {
+      fs.outputFileSync(filePath, '{')
+
+      setTimeout(() => {
+        preprocessor()(file)
+        .catch((err) => {
+          expect(err.stack).to.include('Unexpected token')
+          file.emit('close')
+          done()
+        })
+      }, 1000)
+    })
+  })
 })