import { fork, ChildProcess } from 'child_process' class MockSmtpServer { private static instance: MockSmtpServer private started = false private emailChildProcess: ChildProcess private emails: object[] private constructor () { this.emailChildProcess = fork(`${__dirname}/email-child-process`, []) this.emailChildProcess.on('message', (msg) => { if (msg.email) { return this.emails.push(msg.email) } }) process.on('exit', () => this.kill()) } collectEmails (emailsCollection: object[]) { return new Promise((res, rej) => { if (this.started) { this.emails = emailsCollection return res() } // ensure maildev isn't started until // unexpected exit can be reported to test runner this.emailChildProcess.send({ start: true }) this.emailChildProcess.on('exit', () => { return rej(new Error('maildev exited unexpectedly, confirm port not in use')) }) this.emailChildProcess.on('message', (msg) => { if (msg.err) { return rej(new Error(msg.err)) } this.started = true this.emails = emailsCollection return res() }) }) } kill () { if (!this.emailChildProcess) return process.kill(this.emailChildProcess.pid) this.emailChildProcess = null MockSmtpServer.instance = null } static get Instance () { return this.instance || (this.instance = new this()) } } // --------------------------------------------------------------------------- export { MockSmtpServer }