Ethereum Riddle - https://github.com/JakeLin/ethereum-riddle

generate-address.js

const EC = require('elliptic').ec
const BN = require('bn.js')
const ec = new EC('secp256k1')
const G = ec.g; // Generator point
const keccak256 = require('js-sha3').keccak256

// Refer to https://etherworld.co/2017/11/17/understanding-the-concept-of-private-key-public-key-and-address-in-ethereum-blockchain
/// Get public key from private key. `privateKey` is private key in buffer
const getPublickKeyFromPrivateKey = (privateKey) => {
    if (!(privateKey instanceof Buffer)) {
        throw new TypeError('param privateKey must be of Buffer type');
    }
    
    const pk = new BN(privateKey) // private key as big number
    const publicPoint = G.mul(pk) // EC multiplication to determine public point 
    const x = publicPoint().toBuffer() //32 bit x co-ordinate of public point 
    const y = publicPoint().toBuffer() //32 bit y co-ordinate of public point 
    
    const publicKey = Buffer.concat([x,y])
    return publicKey
}

/// Get address from public key. `publicKey` is public key in buffer
const getAddressFromPublicKey = (publicKey) => {
    if (!(publicKey instanceof Buffer)) {
        throw new TypeError('param privateKey must be of Buffer type');
    }
    
    const hash = keccak256(publicKey)
    const address = Buffer.from(hash, 'hex').slice(-20)
    return address
}

/// Get address from private key. `privateKey` is private key in buffer
const getAddressFromPrivateKey = (privateKey) => {
    if (!(privateKey instanceof Buffer)) {
        throw new TypeError('param privateKey must be of Buffer type');
    }

    const publicKey = getPublickKeyFromPrivateKey(privateKey)
    const address = getAddressFromPublicKey(publicKey)
    return address
}