I am trying to run an example blockchain explorer using testrpc, truffle, webpack and am running into errors.

I am unable to get asynchronous functions to work with Metamask plugin, for example, I am unable to run web3.eth.getBlockNumber.

I tried using filter.watch as explained in some forums but no luck. Can someone help?? I am using code from this example - https://www.codeooze.com/blockchain/ethereum-block-explorer-react-02/

I used filter.watch like this,

filter.watch((error,result) =>{
const block = web3.eth.getBlock(result, true)
this.setState({curr_block: block.number})

I used this solution from How to map a web3 to a react.js state

I was able to add a callback but it doesn't help me capture the return value in a variable. How can I capture the return value using filter.watch?

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