crosshash.js

#!/usr/bin/env node
const MD5 = require('crypto-js/md5');
const stringify = require('json-stable-stringify')

const ERROR_UNSAFE_NUMBER = 'ERROR_UNSAFE_NUMBER'

class CrossHashError extends Error {
    constructor(message) {
        super(message)
        this.name = CrossHashError.name
    }
}

const crosshash = (obj) => {
    return md5(crossjson(obj))
}
const crossjson = (obj) => {
    return stringify(obj, {replacer: replacer})
}

const md5 = (string) => {
    return MD5(string).toString()
}

const replacer = (key, value) => {
    if (typeof value === 'number') {
        validateNumber(value)
    }
    return value
}

const validateNumber = (value) => {
    if (!isSafeNumber(value)) {
        throw new CrossHashError(`${ERROR_UNSAFE_NUMBER}: ${value}`)
    }
}

const isSafeNumber = (value) => {
    return -Number.MAX_SAFE_INTEGER <= value && value <= Number.MAX_SAFE_INTEGER
}

const main = () => {
    const usage = `
    crosshash — stable JSON serialization and hashing for Python and JavaScript

    https://github.com/httpie/crosshash
    
    Usage:
        node crosshash.js --json '{"foo": "bar"}'
        node crosshash.js --hash '{"foo": "bar"}'
    `
    const args = process.argv.slice(2)
    if (args.length !== 2 || !['--json', '--hash'].includes(args[0])) {
        console.log(usage)
        process.exit(1)
    }
    const action = args[0]
    const inputJson = JSON.parse(args[1])
    const operation = {
        '--json': crossjson,
        '--hash': crosshash
    }[action]
    return operation(inputJson)
}

if (typeof require !== 'undefined' && typeof module !== 'undefined' && require.main === module) {
    console.log(main())
}


module.exports = {
    crosshash,
    crossjson,
    CrossHashError,
}