Ejemplo de código de plantillas de correo electrónico de Node.js en 2024

Create, preview (browser/iOS Simulator), and send custom email templates for Node.js. Made for Forward Email and Lad.

Need to send emails that land in the inbox instead of spam folder? Click here to learn how to send JavaScript contact forms and more with Node.js

Install

By default we recommend pug for your template engine, but you can use any template engine. Note that preview-email is an optional dependency and is extremely helpful for rendering development previews of your emails automatically in your browser.

npm:

npm install email-templates preview-email pug

Preview

We've added preview-email by default to this package. This package allows you to preview emails in the browser and in the iOS Simulator.

This means that (by default) in the development environment (e.g. NODE_ENV=development) your emails will be rendered to the tmp directory for you and automatically opened in the browser.

If you have trouble previewing emails in your browser, you can configure a preview option which gets passed along to open's options (e.g. preview: { open: { app: 'firefox' } }).

See the example below for Open Email Previews in Firefox.

Usage

Debugging

Environment Flag

If you run into any issues with configuration, files, templates, locals, etc, then you can use the NODE_DEBUG environment flag:

NODE_DEBUG=email-templates node app.js

This will output to the console all debug statements in our codebase for this package.

Inspect Message

As of v3.6.1 you can now inspect the message passed to nodemailer.sendMail internally.

In the response object from email.send, you have access to res.originalMessage:

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(res => {
    console.log('res.originalMessage', res.originalMessage)
  })
  .catch(console.error);

Basic

You can swap the transport option with a Nodemailer transport configuration object or transport instance. We highly recommend using Forward Email for your transport (it's the default in Lad).

If you want to send emails in development or test environments, set options.send to true.

const Email = require('email-templates');

const email = new Email({
  message: {
    from: 'test@example.com'
  },
  // uncomment below to send emails in development/test env:
  // send: true
  transport: {
    jsonTransport: true
  }
});

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

The example above assumes you have the following directory structure:

.
├── app.js
└── emails
    └── mars
        ├── html.pug
        └── subject.pug

And the contents of the pug files are:

html.pug:

p Hi #{name},
p Welcome to Mars, the red planet.

subject.pug:

= `Hi ${name}, welcome to Mars`

Attachments

Please reference Nodemailer's attachment documentation for further reference.

If you want to set default attachments sent with every email:

const Email = require('email-templates');

const email = new Email({
  message: {
    from: 'test@example.com',
    attachments: [
      {
        filename: 'text1.txt',
        content: 'hello world!'
      }
    ]
  }
});

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

If you want to set attachments sent individually:

const Email = require('email-templates');

const email = new Email({
  message: {
    from: 'test@example.com'
  },
  transport: {
    jsonTransport: true
  }
});

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com',
      attachments: [
        {
          filename: 'text1.txt',
          content: 'hello world!'
        }
      ]
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

Automatic Inline CSS via Stylesheets

Simply include the path or URL to the stylesheet in your template's <head>:

link(rel="stylesheet", href="/css/app.css", data-inline)

This will look for the file /css/app.css in the build/ folder. Also see Optimized Pug Stylesheet Loading below.

If this asset is in another folder, then you will need to modify the default options when creating an Email instance:

const email = new Email({
  // <https://github.com/Automattic/juice>
  juice: true,
  // Override juice global settings <https://github.com/Automattic/juice#juicecodeblocks>
  juiceSettings: {
    tableElements: ['TABLE']
  },
  juiceResources: {
    // set this to `true` (since as of v11 it is `false` by default)
    applyStyleTags: true, // <------------ you need to set this to `true`
    webResources: {
      //
      // this is the relative directory to your CSS/image assets
      // and its default path is `build/`:
      //
      // e.g. if you have the following in the `<head`> of your template:
      // `<link rel="stylesheet" href="style.css" data-inline="data-inline">`
      // then this assumes that the file `build/style.css` exists
      //
      relativeTo: path.resolve('build')
      //
      // but you might want to change it to something like:
      // relativeTo: path.join(__dirname, '..', 'assets')
      // (so that you can re-use CSS/images that are used in your web-app)
      //
    }
  }
});

Render HTML and/or Text

If you don't need this module to send your email, you can still use it to render HTML and/or text templates.

Simply use the email.render(view, locals) method we expose (it's the same method that email.send uses internally).

If you need to render a specific email template file (e.g. the HTML version):

const Email = require('email-templates');

const email = new Email();

email
  .render('mars/html', {
    name: 'Elon'
  })
  .then(console.log)
  .catch(console.error);

The example above assumes you have the following directory structure (note that this example would only render the html.pug file):

.
├── app.js
└── emails
    └── mars
        ├── html.pug
        ├── text.pug
        └── subject.pug

The Promise for email.render resolves with a String (the HTML or text rendered).

If you need pass juiceResources in render function, with this option you don't need create Email instance every time

const Email = require('email-templates');

const email = new Email();

email
  .render({
    path: 'mars/html',
    juiceResources: {
      webResources: {
        // view folder path, it will get css from `mars/style.css`
        relativeTo: path.resolve('mars')
      }
    }
  }, {
    name: 'Elon'
  })
  .then(console.log)
  .catch(console.error);

The example above will be useful when you have a structure like this, this will be useful when you have a separate CSS file for every template

.
├── app.js
└── emails
    └── mars
        ├── html.pug
        ├── text.pug
        ├── subject.pug
        └── style.css

The Promise for email.render resolves with a String (the HTML or text rendered).

If you need to render all available template files for a given email template (e.g. html.pug, text.pug, and subject.pug – you can use email.renderAll (this is the method that email.send uses).

const Email = require('email-templates');

const email = new Email();

email
  .renderAll('mars', {
    name: 'Elon'
  })
  .then(console.log)
  .catch(console.error);

If you need to render multiple, specific templates at once (but not all email templates available), then you can use Promise.all in combination with email.render:

const Email = require('email-templates');

const email = new Email();
const locals = { name: 'Elon' };

Promise
  .all([
    email.render('mars/html', locals),
    email.render('mars/text', locals)
  ])
  .then(([ html, text ]) => {
    console.log('html', html);
    console.log('text', text);
  })
  .catch(console.error);

Localization

All you need to do is simply pass an i18n configuration object as config.i18n (or an empty one as this example shows to use defaults).

Don't want to handle localization and translation yourself? Just use Lad – it's built in and uses mandarin (with automatic Google Translate support) under the hood.

const Email = require('email-templates');

const email = new Email({
  message: {
    from: 'test@example.com'
  },
  transport: {
    jsonTransport: true
  },
  i18n: {} // <------ HERE
});

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      locale: 'en', // <------ CUSTOMIZE LOCALE HERE (defaults to `i18n.defaultLocale` - `en`)
      // is your user french?
      // locale: 'fr',
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

Then slightly modify your templates to use localization functions.

html.pug:

p= `${t('Hi')} ${name},`
p= t('Welcome to Mars, the red planet.')

subject.pug:

p= `${t('Hi')} ${name}, ${t('welcome to Mars')}`

Note that if you use Lad, you have a built-in filter called translate:

p: :translate(locale) Welcome to Mars, the red planet.

Localization using Handlebars template engine

If you are using handlebars and you are using localization files with named values, you will quickly see that there is no way to properly call the t function in your template and specify named values.

If, for example you have this in your translation file:

{
  "greetings": "Hi {{ firstname }}",
  "welcome_message": "Welcome to Mars, the red planet."
}

And you would like to use it in your template like this:

html.hbs:

<p>{{ t "greetings" firstname="Marcus" }}</p>
<p>{{ t "welcome_message" }}</p>

This would not work because the second argument sent by handlebars to the function would be a handlebar helper options object instead of just the named values.

A possible workaround you can use is to introduce your own translation helper in your template locals:

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      locale: 'en', // <------ CUSTOMIZE LOCALE HERE (defaults to `i18n.defaultLocale` - `en`)
      // is your user french?
      // locale: 'fr',
      name: 'Elon',
      $t(key, options) {
        // <------ THIS IS OUR OWN TRANSLATION HELPER
        return options.data.root.t(
          { phrase: key, locale: options.data.root.locale },
          options.hash
        );
      }
    }
  })
  .then(console.log)
  .catch(console.error);

Then slightly modify your templates to use your own translation helper functions.

html.hbs:

<p>{{ $t "greetings" firstname="Marcus" }}</p>
<p>{{ $t "welcome_message" }}</p>

Text-Only Email (no HTML)

If you wish to have only a text-based version of your email you can simply pass the option textOnly: true.

Regardless if you use the htmlToText option or not (see next example), it will still render only a text-based version.

const Email = require('email-templates');

const email = new Email({
  message: {
    from: 'test@example.com'
  },
  transport: {
    jsonTransport: true
  },
  textOnly: true // <----- HERE
});

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

Prefix Subject Lines

You can pass an option to prefix subject lines with a string, which is super useful for deciphering development / staging / production environment emails.

For example, you could make it so on non-production environments the email is prefixed with a [DEVELOPMENT] Some Subject Line Here.

You could do this manually by passing a message.subject property, however if you are storing your subject lines in templates (e.g. subject.ejs or subject.pug) then it's not as easy.

Simply use the subjectPrefix option and set it to whatever you wish (note you will need to append a trailing space if you wish to have a space after the prefix; see example below):

const Email = require('email-templates');

const env = process.env.NODE_ENV || 'development';

const email = new Email({
  message: {
    from: 'test@example.com'
  },
  transport: {
    jsonTransport: true
  },
  subjectPrefix: env === 'production' ? false : `[${env.toUpperCase()}] `; // <--- HERE
});

Custom Text Template

By default we use html-to-text to generate a plaintext version and attach it as message.text.

If you'd like to customize the text body, you can pass message.text or create a text template file just like you normally would for html and subject.

You may also set config.htmlToText: false to force the usage of the text template file.

const Email = require('email-templates');

const email = new Email({
  message: {
    from: 'test@example.com'
  },
  transport: {
    jsonTransport: true
  },
  htmlToText: false // <----- HERE
});

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

text.pug:

| Hi #{name},
| Welcome to Mars, the red planet.

Custom Template Engine (e.g. EJS)

1. Install your desired template engine (e.g. EJS)

   npm:

   npm install ejs
   

2. Set the extension in options and send an email

   const Email = require('email-templates');
   
   const email = new Email({
     message: {
       from: 'test@example.com'
     },
     transport: {
       jsonTransport: true
     },
     views: {
       options: {
         extension: 'ejs' // <---- HERE
       }
     }
   });
   

Custom Default Message Options

You can configure your Email instance to have default message options, such as a default "From", an unsubscribe header, etc.

For a list of all available message options and fields see the Nodemailer message reference.

Here's an example showing how to set a default custom header and a list unsubscribe header:

const Email = require('email-templates');

const email = new Email({
  message: {
    from: 'test@example.com',
    headers: {
      'X-Some-Custom-Thing': 'Some-Value'
    },
    list: {
      unsubscribe: 'https://example.com/unsubscribe'
    }
  },
  transport: {
    jsonTransport: true
  }
});

Custom Rendering (e.g. from a MongoDB database)

You can pass a custom config.render function which accepts two arguments view and locals and must return a Promise.

Note that if you specify a custom config.render, you should have it use email.juiceResources before returning the final HTML. The example below shows how to do this.

If you wanted to read a stored EJS template from MongoDB, you could do something like:

const ejs = require('ejs');

const email = new Email({
  // ...
  render: (view, locals) => {
    return new Promise((resolve, reject) => {
      // this example assumes that `template` returned
      // is an ejs-based template string
      // view = `${template}/html` or `${template}/subject` or `${template}/text`
      db.templates.findOne({ name: view }, (err, template) => {
        if (err) return reject(err);
        if (!template) return reject(new Error('Template not found'));
        let html = ejs.render(template, locals);
        html = await email.juiceResources(html);
        resolve(html);
      });
    });
  }
});

Absolute Path to Templates

As of v5.0.1+ we now support passing absolute paths to templates for rendering (per discussion in #320.

For both email.send and email.render, the template option passed can be a relative path or absolute:

Relative example:

email
  .send({
    template: 'mars',
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

Absolute example:

const path = require('path');

// ...

email
  .send({
    template: path.join(__dirname, 'some', 'folder', 'mars')
    message: {
      to: 'elon@spacex.com'
    },
    locals: {
      name: 'Elon'
    }
  })
  .then(console.log)
  .catch(console.error);

Open Email Previews in Firefox

The preview option can be a custom Object of options to pass along to open's options.

Firefox example:

const email = new Email({
  // ...
  preview: {
    open: {
      app: 'firefox',
      wait: false
    }
  }
});

Options

For a list of all available options and defaults view the configuration object, or reference the list below:

• views (Object)
  • root (String) - defaults to the current working directory's "emails" folder via path.resolve('emails')
  • options (Object)
    • extension (String) - defaults to 'pug', and is the default file extension for templates
    • map (Object) - a template file extension mapping, defaults to { hbs: 'handlebars', njk: 'nunjucks' } (this is useful if you use different file extension naming conventions)
    • engineSource (Object) - the default template engine source, defaults to @ladjs/consolidate
  • locals (Object) - locals to pass to templates for rendering
    • cache (Boolean) - defaults to false for development and test environments, and true for all others (via process.env.NODE_ENV), whether or not to cache templates
    • pretty (Boolean) - defaults to true, but is automatically set to false for subject templates and text-based emails
• message (Object) - default Nodemailer message object for messages to inherit (defaults to an empty object {})
• send (Boolean) - whether or not to send emails, defaults to false for development and test environments, and true for all others (via process.env.NODE_ENV) (NOTE: IF YOU ARE NOT USING NODE_ENV YOU WILL NEED TO MANUALLY SET THIS TO true)
• preview (Boolean or Object) - whether or not to preview emails using preview-email, defaults to false unless the environment is development (via process.env.NODE_ENV) – if you wish to disable the iOS Simulator then pass { openSimulator: false }
• i18n (Boolean or Object) - translation support for email templates, this accepts an I18N configuration object (defaults to false, which means it is disabled) which is passed along to @ladjs/i18n – see Localization example for more insight
• render (Function) - defaults to a stable function that accepts two argument, view (String) and locals (Object) - you should not need to set this unless you have a need for custom rendering (see Custom Rendering (e.g. from a MongoDB database))
• customRender (Boolean) - defaults to false, unless you pass your own render function, and in that case it will be automatically set to true
• textOnly (Boolean) - whether or not to force text-only rendering of a template and disregard the template folder (defaults to false)
• htmlToText (Object) - configuration object for html-to-text
  • ignoreImage (Boolean) - defaults to true
• subjectPrefix (Boolean or String) - defaults to false, but if set to a string it will use that string as a prefix for your emails' subjects
• juice (Boolean) - whether or not to use juice when rendering templates (defaults to true) (note that if you have a custom rendering function you will need to implement juice in it yourself)
• juiceResources (Object) - options to pass to juice.juiceResources method (only used if juice option is set to true, see juice's API for more information
  • applyStyleTags (Boolean) - defaults to false (as of v11, since modern browsers now support <style> tag in <head> section)
  • removeStyleTags (Boolean) - defaults to false (as of v11, since modern browsers now support <style> tag in <head> section)
  • webResources (Object) - an options object that will be passed to web-resource-inliner
    • relativeTo (String) - defaults to the current working directory's "build" folder via path.resolve('build') (NOTE: YOU SHOULD MODIFY THIS PATH TO WHERE YOUR BUILD/ASSETS FOLDER IS)
    • images (Boolean or Number) - defaults to false, and is whether or not to inline images unless they have an exclusion attribute (see web-resource-inliner for more insight), if it is set to a Number then that is used as the KB threshold
• transport (Object) - a transport configuration object or a Nodemailer transport instance created via nodemailer.createTransport, defaults to an empty object {}, see Nodemailer transports documentation for more insight
• getPath (Function) - a function that returns the path to a template file, defaults to function (type, template) { return path.join(template, type); }, and accepts three arguments type, template, and locals

Tips

Purge unused CSS

See the gulpfile.js file and email directory in the Forward Email codebase for insight as to how to use purge-css across your email templates.

Optimized Pug Stylesheet Loading

Note that if you're using pug, you can use the following pattern to optimize compile time for rendering in your email layout.

doctype html
html
  head
-    link(rel='stylesheet', href='style.css', data-inline)
+    style
+      include style.css
  body
    p Hello

This makes use of pug includes – which saves compilation time for rendering (since web-resource-inliner will not have to fetch the external stylesheet).

Plugins

You can use any nodemailer plugin. Simply pass an existing transport instance as config.transport.

You should add the nodemailer-base64-to-s3 plugin to convert base64 inline images to actual images stored on Amazon S3 and Cloudfront.

When doing so (as of v4.0.2+), you will need to adjust your email-templates configuration to pass images: true as such:

const email = new Email({
  // ...
  juiceResources: {
    webResources: {
      relativeTo: path.resolve('build'),
      images: true // <--- set this as `true`
    }
  }
});

Breaking Changes

See the Releases page for an up to date changelog.

v12.0.0

The preview-email dependency is now an optional dependency. You will need to npm install preview-email or set preview: false, otherwise an error will be thrown in non-production environments and console.error in production environments if preview option is a truthy value. The default value for preview is preview: process.NODE_ENV === 'development'.

v11.0.0

This package no longer inlines stylesheets by default and preserves <style> tags in the <head> (see Options).

A majority of email clients support <style> tags in the <head> section – and inlining CSS is no longer necessary.

See 1, 2, and 3 as references.

v10.0.0

This package now requires Node v14+.

v9.0.0

This package now requires Node v10.x+ due to web-resource-inliner dependency.

v8.0.0

We upgraded html-to-text to v6. As a result, automatically generated text versions of your emails will look slightly different, as per the example below:

+Hi,
+
+email-templates rocks!
+
+Cheers,
+The team
-Hi,email-templates rocks!
-Cheers,The team

v7.0.0

We upgraded preview-email to v2.0.0, which supports stream attachments, and additionally the view rendering is slightly different (we simply iterate over header lines and format them in a <pre><code> block). A major version bump was done due to the significant visual change in the preview rendering of emails.

v6.0.0

• Performance should be significantly improved as the rendering of subject, html, and text parts now occurs asynchronously in parallel (previously it was in series and had blocking lookup calls).

• We removed bluebird and replaced it with a lightweight alternative pify (since all we were using was the Promise.promisify method from bluebird as well).

• This package now only supports Node v8.x+ (due to preview-email's open dependency requiring it).

• Configuration for the preview option has slightly changed, which now allows you to specify a custom template and stylesheets for preview rendering.

  If you were using a custom preview option before, you will need to change it slightly:

  const email = new Email({
    // ...
    preview: {
  +    open: {
  +      app: 'firefox',
  +      wait: false
  +    }
  -    app: 'firefox',
  -    wait: false
    }
  });
  

v5.0.0

In version 4.x+, we changed the order of defaults being set. See #313 for more information. This allows you to override message options such as from (even if you have a global default from set).

v4.0.0

See v5.0.0 above

v3.0.0

If you are upgrading from v2 or prior to v3, please note that the following breaking API changes occurred:

1. You need to have Node v6.4.0+, we recommend using nvm to manage your Node versions.

2. Instead of calling const newsletter = new EmailTemplate(...args), you now call const email = new Email(options).

   • The arguments you pass to the constructor have changed as well.
   • Previously you'd pass new EmailTemplate(templateDir, options). Now you will need to pass simply one object with a configuration as an argument to the constructor.
   • If your templateDir path is the "emails" folder in the root of your project (basically ./emails folder) then you do not need to pass it at all since it is the default per the configuration object.
   • The previous value for templateDir can be used as such:

   -const newsletter = new EmailTemplate(templateDir);
   +const email = new Email({
   +  views: { root: templateDir }
   +});
   

   • Note that if you are inlining CSS, you should also make sure that the option for juiceResources.webResources.relativeTo is accurate.

3. Instead of calling newsletter.render(locals, callback) you now call email.render(template, locals). The return value of email.render when invoked is a Promise and does not accept a callback function.

   NOTE: email-templates v3 now has an email.send method (see basic usage example) which uses nodemailer; you should now use email.send instead of email.render!

   -newsletter.render({}, (err, result) => {
   -  if (err) return console.error(err);
   -  console.log(result);
   -});
   +email.render(template, {}).then(console.log).catch(console.error);
   

4. Localized template directories are no longer supported. We now support i18n translations out of the box. See Localization for more info.

5. A new method email.send has been added. This allows you to create a Nodemailer transport and send an email template all at once (it calls email.render internally). See the Basic usage documentation above for an example.

6. There are new options options.send and options.preview. Both are Boolean values and configured automatically based off the environment. Take a look at the configuration object. Note that you can optionally pass an Object to preview option, which gets passed along to open's options.

7. If you wish to send emails in development or test environment (disabled by default), set options.send to true.

Related

• forward-email - Free, encrypted, and open-source email forwarding service for custom domains
• custom-fonts-in-emails - render any font in emails as an image w/retina support (no more Photoshop or Sketch exports)
• font-awesome-assets - render any Font Awesome icon as an image in an email w/retina support (no more Photoshop or Sketch exports!)
• lad - Scaffold a Koa webapp and API framework for Node.js
• lass - Scaffold a modern boilerplate for Node.js
• cabin - Logging and analytics solution for Node.js, Lad, Koa, and Express