Parse e-mails using mailparser to get decoded plain-text

[tillsanders]

I had problems with a test where the assertion was unable to find a certain string in the e-mail body since it was encoded. More specifically, special chars were encoded and line breaks where added mid-word (I still don't know the reason for that). The plain-text was encoded using the quoted-printable pattern. I found a library for decoding but first I would need to extract the encoded plain-text from the e-mail. At that point I decided to integrate mailparser to properly access the e-mail contents.

I believe cypress-mailhog could benefit from this solution, but I don't have the resources to make a PR myself, right now. So here is how I integrated mailparser, maybe someone else has the time to do this properly.

First, add a new command:

// cypress/support/index.d.ts

/// <reference types="cypress" />

declare namespace Cypress {
  interface Chainable {
    mhParseMail(): Chainable<string>
  }
}

// cypress/support/commands.ts

/// <reference path="../../node_modules/cypress-mailhog/types/mailhog.d.ts" />

Cypress.Commands.add('mhParseMail', { prevSubject: true }, (mail: any) => {
  return cy.task('parse-mail', { mail: (mail as mailhog.Item).Raw.Data })
})

As you can see, this command calls a task. Sadly, mailparser is not browser-compatible:

// cypress/plugins/index.js

const simpleParser = require('mailparser').simpleParser

module.exports = async (on, config) => {
  on('task', {
    'parse-mail': ({ mail }) => simpleParser(mail),
  })
}

Obviously, we also need to install mailparser: npm i -D mailparser.

Then in your test, you can use it like this:

// ...

cy.mhGetMailsByRecipient('[email protected]')
  .mhFirst()
  .mhParseMail()
  .its('text')
  .should('contain', 'foo')

Now that we have mailparser integrated, you can also use it to access lots of other properties. See the mailparser docs for details: https://nodemailer.com/extras/mailparser/#mail-object