How to calculate the txHash?

Question

When i have a rawTx ,such as this '15e2d20fae45d0c19a01177b48c79f1298a3343b2f4a4286ec27b7bdca0ae8cb070000e7fb71f07fb0a5ac3ec398f6ad47c10730d2145ff309bcdd04f855ac0200cc5febf12dc07f8e71b6f73d485ea733a77c3908d1b4e9bb0582579edb762756080000e7fb71f07fb0a5ac3ec398f6ad47c10730d2145ff309bddd04f855ac02e09143000056a48224cb245a4ede4774d377e94fd01d0a7eefff00000002030b35676fe47e2d12a184e7693640e8ab6ac1d3fa640b5da03ea1b9d1649e55383f6e58a330602fdc1f5dd028b4e0e948e1cbc78565a70027cfcb2d6a955412010d' how to get the txHash?

Answer 1

1. Create a 32 byte generic hash of the raw tx
2. Base58 encode it with the 'o' prefix

It would look something like this:

var rawHash = libsodium.crypto_generichash(32, rawTx);
var prefix = new Uint8Array([5, 116]); // 'o'
var merged = new Uint8Array(prefix.length + rawHash.length);
merged = merged.set(prefix);
merged = merged.set(rawHash, prefix.length);
var txHash = Bs58check.encode(merged);