fix: use JSON.stringify(..) for logging instead of String(..)

client/src/client/workers/test-evaluator.js

@@ -4,13 +4,18 @@ import __toString from 'lodash/toString';
 
 const oldLog = self.console.log.bind(self.console);
 self.console.log = function proxyConsole(...args) {
-  self.postMessage({ type: 'LOG', data: String(args) });
+  self.postMessage({
+    type: 'LOG',
+    data: args.map(log => JSON.stringify(log)).join(' ')
+  });
   return oldLog(...args);
 };
 
 self.onmessage = async e => {
   /* eslint-disable no-unused-vars */
-  const { code = '' } = e.data;
+  const {
+    code = ''
+  } = e.data;
   const assert = chai.assert;
   // Fake Deep Equal dependency
   const DeepEqual = (a, b) => JSON.stringify(a) === JSON.stringify(b);
@@ -35,7 +40,9 @@ self.onmessage = async e => {
     if (typeof testResult === 'function') {
       await testResult(fileName => __toString(e.data.sources[fileName]));
     }
-    self.postMessage({ pass: true });
+    self.postMessage({
+      pass: true
+    });
   } catch (err) {
     self.postMessage({
       err: {