Estimation of blocks time generation programmatically

Question

What is the correct way to estimate blocks time generation for chain with Web3?

Answer 1

Because we know block times do not overlap the easiest approach (taking only 3 queries). Just grab the current block and a block X blocks before the current block, subtract the time of the old block from the new block. That will give you how long it took for X blocks. Dived that by X to get the average time per block.

So here with X = 500

  var nowBlock;
  // Get the current block number
  web3.eth.getBlockNumber(function(err, nowBlockNumber) {
    // Get the current block
    web3.eth.getBlock(nowBlockNumber, function(err, nb) {
      nowBlock = nb;
      // Get the block 500 blocks ago
      web3.eth.getBlock(nowBlockNumber - 500, function(err, thenBlock) {
        // Take the average of the then and now timestamps
        KTC.averageBlockTime = (nowBlock.timestamp - thenBlock.timestamp) / 500.0;
      });
    });
  });

Answer 2

Here's a version expanded from Viktor Baranov's answer that takes the average of the last 100 blocks.

const getBlockAverageTime = async () => {
  const span = 100
  const times = []
  const currentNumber = await web3.eth.getBlockNumber()
  const firstBlock = await web3.eth.getBlock(currentNumber - span)
  let prevTimestamp = firstBlock.timestamp

  for (let i = currentNumber - span + 1; i <= currentNumber; i++) {
    const block = await web3.eth.getBlock(i)
    let time = block.timestamp - prevTimestamp
    prevTimestamp = block.timestamp
    times.push(time)
  }

  return Math.round(times.reduce((a, b) => a + b) / times.length)
}

Answer 3

calculateBlockTimeGeneration(web3, function(err, blockTimeGeneration) {
    if (err) return console.log(err);
    console.log("Block time generation in seconds: " + blockTimeGeneration);
});


function calculateBlockTimeGeneration(web3, cb) {
    web3.eth.getBlockNumber(function(err, curBlock) {
        if (err) return cb(err);
        let prevBlock = curBlock - 1;
        let prevBlockInfo = web3.eth.getBlock(prevBlock);
        let curBlockInfo = web3.eth.getBlock(curBlock);
        let blockTimeGeneration = curBlockInfo.timestamp - prevBlockInfo.timestamp;
        cb(null, blockTimeGeneration);
    });
}

Please, post your answer, if it could be made easier.

Answer 4

I wrote two Medium articles (here and here) that looked at block production per week.

Looking at how many blocks are produced over a constant amount of "real-world" time is revelatory. The effect of the difficulty bomb (even it's double nature) become obvious.

All I really did was scan the block timestamps and whenever it was Sunday morning at 12:00 midnight, I printed out the block number since the previous Sunday morning at midnight and their differences to get blocks/week.