es.ts

#!/usr/bin/env ts-node
import { createHash } from 'crypto'

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

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

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

Also see

• es.js
• es.sh