How to check if a transaction is pending?

Question

I tried to send a signedTransaction using a low gas price (it's my will to test timeoute of my scripts)

I supposed also that a not mined transaction was 'pending', so I tried checking, while the first transaction has not been mined yet, using

web3.eth.getPendingTransactions();

I got every time an empty array.

Why?

So, what is a pending transaction?

Answer 1

This function returns all pending transactions in a node's mempool, but it doesn't work in Web3.js.

To read a node's mempool using Web3.js, you need to add a custom call -

//add txpool support
web3.extend({
   property: 'txpool',
   methods: [{
      name: 'content',
      call: 'txpool_content'
   }]
})

Then call it -

web3.txpool.content((err, data) => {
   console.log(err, data)
});

If you want to check a specific transaction status, you can use web3.eth.getTransactionReceipt(txHash), if you get null, that transaction wasn't mined yet (still pending).

Answer 2

web3.eth.getPendingTransactions(); returns an empty array because it's supposed to only return the transactions originating from an account on the node itself (not all pending transactions). Check source.

Good explanation here too.