Uncaught TypeError: Cannot read property '0' of undefined

[Simoneth]

Issue Type

Uncaught TypeError: Cannot read property '0' of undefined
    at http://localhost:8080/app.js:29773:34
    at Array.map (native)
    at Object.decodeEvent (http://localhost:8080/app.js:29772:6)
    at http://localhost:8080/app.js:33803:38
    at Array.map (native)
    at Object.decodeLogs (http://localhost:8080/app.js:33774:19)
    at Object.callback (http://localhost:8080/app.js:33896:35)
    at http://localhost:8080/app.js:6974:25
    at http://localhost:8080/app.js:37588:9
    at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/scripts/inpage.js:168:7

Description

On a private-network on port 8545 using testrpc and MetaMask when I send coins to another account I get this error

Steps to reproduce

On Windows
Prompt1
truffle.cmd init webpack

Prompt2
testrpc

Prompt1
truffle.cmd compile
truffle.cmd migrate
npm run dev

Go to localhost:8080

Versions

• Node/NPM: Node 8.0 npm 5.0.3
• Browser: Chrome

[SilentCicero]

What version of Truffle are you using, can you post anything about how you are using this method?

It's most likely caused by Truffle using decodeEvent with some inputs your feeding it. So it could just be your inputs, or something internally with Truffle, potentially due to a recent update (v3.3 Lemon) I doubt its ethjs-abi however, as we have not changed much in the past while. I'll ping tim. @tcoulter any thoughts?

[tomw1808]

I am getting the same error, with the truffle-init-webpack project.

Here's the steps I have taken on a clean environment:

npm install -g truffle@beta
npm install -g ethereumjs-testrpc@beta
truffle init webpack
... compile and start testrpc ...
npm run dev

open in chrome inkl Metamask
connect meta-mask to localhost
import one account from testrpc to metamask
transfer a MetaCoin to another account.

Same happens on Firefox without MetaMask in the middle.

I also think it is not really related to ethjs-abi, because as far as I can tell the function where it fails (decodeEvent(...)) has not changed since version 0.0.1. Haven't had the chance to dig deeper yet, any pointers would be helpful though.

Thanks,
Thomas

[Simoneth]

What version of Truffle are you using, can you post anything about how you are using this method?

I'm using the exact same method as @tomw1808 with Truffle beta.

[anuragverma639]

I am also getting the same error, with truffle init webpack project.

[Ericxgao]

I am also getting the same issue with the steps above. This has to do with whether or not I define an event parameter as indexed (removing it fixes the issue).

[SilentCicero]

Will take a look at this, thanks, I'll talk with Tim, he didn't seemed too bothered by this before.

…

Sent from my iPhone

On Jul 13, 2017, at 3:40 PM, Ericxgao ***@***.***> wrote: I am also getting the same issue with the steps above. This has to do with whether or not I define an event parameter as indexed (removing it fixes the issue). — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[tcoulter]

I haven't been able to reproduce the issue with the steps provided.

@tomw1808 You gave these steps:

npm install -g truffle@beta
npm install -g ethereumjs-testrpc@beta
truffle init webpack
... compile and start testrpc ...
npm run dev

You didn't list migrating (i.e., deploying) your contracts. Did you perform that step before continuing?

Can you tell me what operating system you guys are using? So far it looks like Windows.

[francescovalentino]

@tcoulter

Yes, Windows 8.1 64-bit

[tcoulter]

I've successfully reproduced, but only on Windows. Diagnosing.

[tcoulter]

I've found the culprit, though I don't understand it.

TL;DR: npm is installing the wrong version of ethjs-abi.

Background:

If you look here, truffle-init-webpack is asking for a version of truffle-contract that's v1.1.6 or above, in which case npm should choose the latest version, which is v1.1.11. Version v1.1.11 fixes the issue above by pinning the expected version of ethjs-abi; however, on Windows, npm choose v1.1.6 of truffle-contract instead of v1.1.11, which installs the incorrect version of ethjs-abi. I don't know why the behavior of npm on Windows and Mac is different, but of course this is software, so c'est la vie.

Solution

I'll bump a version of truffle-init-webpack momentarily that fixes this issue.

Obligatory aside: Note that we're moving away from truffle-init-webpack in favor of Truffle Boxes, which offer a better experience and more options (and a larger set of boxes once we can get new ones rolled out). You should check them out if you haven't already!

[tcoulter]

This has been fixed. You should now be able to perform the following on Windows with no issue:

truffle init webpack
truffle compile
truffle migrate
npm run dev

You'll be able to use the example application as expected.

Cheers! @SilentCicero, you can close this issue.

[tomw1808]

Hey @tcoulter sorry the late reply and thanks for fixing it.

OT question: Moving away from truffle-init-webpack and into the truffle boxes is understandable. They are great. But will there be a box that starts with vanilla JS and just implements a basic build environment for javascript? Webpack was pretty convenient to have just that without the hassle of scaffolding for a quick vanilla js Dapp-project for prototyping. Any recommendations on that side?