Reject Transaction in Firefox does not throw 'User denied transaction signature' error

[rsmylskibc]

Bug Reports:

When rejecting a transaction in Firefox, it looks like an unexpected error is thrown instead of the User denied transaction signature... error that is thrown in Chrome.

• Expected Behavior
  There should be the User denied transaction signature... error thrown

• Actual Behavior
  The following error is thrown:
  Returned error: e/</</<@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:37411
  n@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:861365
  [401]</n.prototype.emit@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:860181
  value@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:85832
  value@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:84876
  e/<@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:42639
  _@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1079026
  [543]</w/o._invoke@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1078816
  [543]</E/</e[t]@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1079202
  n@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:385866
  [130]</r.default/</<@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:385849
  S@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:633657
  [130]</r.default/<@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:385805
  [15]</t.exports</<.value</<@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:42754
  [27]</t.exports/<@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:58607
  [334]</u.prototype.apply@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:676490
  [334]</u.prototype.handle@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:676192
  [340]</</a.prototype.handle@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:679853
  [340]</</a.prototype.write@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:679764
  m@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1059053
  [401]</n.prototype.emit@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:860181
  _@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1053892
  w@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1053709
  [532]</</y.prototype.push@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1054520
  _write@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1017826
  v@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1066676
  [534]</</g.prototype.write/a<@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1069790
  [534]</</g.prototype.write@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1069302
  m@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1059053
  [401]</n.prototype.emit@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:860181
  _@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1053892
  w@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1053709
  [532]</</y.prototype.push@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:1054520
  [33]</</o.prototype._onMessage@moz-extension://b009ab06-08cf-4d7e-a083-7cc4d8b4ac13/scripts/background.js:1:75842

• Browser Used
  Firefox 59.0

• Operating System Used
  Windows 10

[tmashuang]

A lot of changes have happened since this issue regarding error messages. We have expanded the error object and now might need to grab the message from the error object. For example testing on latest build:

web3.eth.sendTransaction({}, (error, result) => {
  error ? console.log(error.message) : console.log(result)
})

If this is no longer the case in the future feel free to open a new PR with an example implementation.