Mailspring/docs/ComposerExtensions.md
Evan Morikawa 11b731891f feat(extension): async extensions
Summary:
WIP:

This is a quick patch for Drew to make extensions async

We'll need to think through the upgrade/deprecation plan to roll out async
extensions across all of our APIs.

Test Plan: TODO

Reviewers: drew, evan, bengotow

Reviewed By: bengotow

Differential Revision: https://phab.nylas.com/D2392
2015-12-30 18:04:52 -05:00

47 lines
1.7 KiB
Markdown

---
Title: Extending the Composer
Section: Guides
Order: 6
---
The composer lies at the heart of N1, and many improvements to the mail experience require deep integration with the composer. To enable these sort of plugins, the {DraftStore} exposes an extension API.
This API allows your package to:
- Display warning messages before a draft is sent. (ie: "Are you sure you want to send this without attaching a file?")
- Intercept keyboard and mouse events to the composer's text editor.
- Transform the draft and make additional changes before it is sent.
To create your own composer extensions, subclass {ComposerExtension} and override the methods your extension needs.
In the sample packages repository, [templates]() is an example of a package which uses a ComposerExtension to enhance the composer experience.
### Example
This extension displays a warning before sending a draft that contains the names of competitors' products. If the user proceeds to send the draft containing the words, it appends a disclaimer.
```coffee
{ComposerExtension} = require 'nylas-exports'
class ProductsExtension extends ComposerExtension
@warningsForSending: ({draft}) ->
words = ['acme', 'anvil', 'tunnel', 'rocket', 'dynamite']
body = draft.body.toLowercase()
for word in words
if body.indexOf(word) > 0
return ["with the word '#{word}'?"]
return []
@finalizeSessionBeforeSending: ({session}) ->
draft = session.draft()
if @warningsForSending({draft})
bodyWithWarning = draft.body += "<br>This email \
contains competitor's product names \
or trademarks used in context."
return session.changes.add(body: bodyWithWarning)
else return Promise.resolve()
```