es.js

#!/usr/bin/env node
'use strict'

const { createHash } = require('crypto')

function slugSha256(data) {
    return Number(`0x${createHash('sha256').update(data).digest('hex').slice(0, 8)}`)
}

function functionHash(signature) {
    let hash = slugSha256(signature.replaceAll(' ', ''))
    // FIXME for constructor, cell, bytes see https://gist.github.com/ilyar/484360bdb5464a6f252bd8f8ec10aaff
    return signature.includes('constructor') ? hash ^ 2 ** 31 : hash
}

function functionID(signature) {
    return `0x${functionHash(signature + 'v2').toString(16)}`
}

console.log(functionID(process.argv[2]))

$ node es.js "main()(string)"
0xb0992770
$ node es.js "redeem(uint256, string, uint256)()"
0x58160fa0
$ bash es.js "constructor()()"
0x68b55f3f

Also see

• es.ts
• es.sh