How to derive public child keys from public parent keys with bip39-libs.js?

Question

I red this doc: https://howieliux.github.io/assets/others/Mastering_bitcoin/Mastering_Bitcoin.html

and found:

As mentioned previously, a very useful characteristic of HD wallets is the ability to derive public child keys from public parent keys, without having the private keys. This gives us two ways to derive a child public key: either from the child private key, or directly from the parent public key.

An extended public key can be used, therefore, to derive all of the public keys (and only the public keys) in that branch of the HD wallet structure.

Which method of bip39-lib.js I need to call to derive address from public parent keys? I haven't found any reference in the doc.

https://github.com/bitcoinjs/bip39

Answer 1

bip39-lib.js works along with bip32-lib.js AND bitcoinjs-lib.

BIP39 is strictly regarding the mnemonic phrase and HD seed.

In order to derive child keys from an HD seed you'll also need to use BIP32.

BUT... BIP32 has no concept of addresses either so ultimately you'll also need bitcoinjs-lib.

In other words you need to use all three libraries to go from mnemonic to a usable address.