index.js

'use strict'

const punycode = require('punycode/')
const nearley = require('nearley')

const grammar = nearley.Grammar.fromCompiled(require('./grammar.js'))
grammar.start = 'main'

// a class encapsulating an email address per RFC-5321

class Address {
    constructor(user, host) {
        if (typeof user === 'object' && user.original) {
            // Assume constructing from JSON parse
            for (const k in user) {
                this[k] = user[k]
            }
            return this
        }
        if (!host) {
            this.original = user
            this.parse(user)
        } else {
            this.original = `${user}@${host}`
            this.user = user
            this.original_host = host

            if (/[\u0080-\uFFFF]/.test(host)) {
                this.is_utf8 = true
                host = punycode.toASCII(host)
            }

            this.host = host.toLowerCase()
        }
    }

    parse(addr) {
    // empty addr is ok
        if (addr === '' || addr === '<>') {
            this.user = ''
            this.host = ''
            return
        }

        // bare postmaster is permissible: RFC-5321 (4.1.1.3)
        switch (addr.toLowerCase()) {
            case 'postmaster':
            case '<postmaster>':
                this.user = 'postmaster'
                this.host = ''
                return
        }

        const parser = new nearley.Parser(grammar)

        parser.feed(addr)
        const result = parser.results[0][0]

        let domainpart = result.domain
        this.original_host = domainpart

        if (/[\u0080-\uFFFF]/.test(domainpart)) {
            this.is_utf8 = true
            domainpart = punycode.toASCII(domainpart)
        }

        this.host = domainpart.toLowerCase()
        this.user = result.local_part
    }

    isNull() {
        return this.user ? 0 : 1
    }

    format(use_punycode) {
        if (this.isNull()) return '<>'

        return `<${this.address(null, use_punycode)}>`
    }

    address(set, use_punycode) {
        if (set) {
            this.original = set
            this.parse(set)
        }
        return (
            (this.user || '') +
      (this.original_host
          ? `@${use_punycode ? this.host : this.original_host}`
          : '')
        )
    }

    toString() {
        return this.format()
    }
}

exports.Address = Address