@fastify/view
Templates rendering plugin support for Fastify.
@fastify/view decorates the reply interface with the view and viewAsync methods for managing view engines, which can be used to render templated responses.
Currently supports the following templates engines:
In production mode, @fastify/view will heavily cache the templates file and functions, while in development will reload every time the template file and function.
Note: For Fastify v3 support, please use point-of-view 5.x (npm i point-of-view@5).
Note that at least Fastify v2.0.0 is needed.
Recent Changes
Note: reply.viewAsync added as a replacement for reply.view and fastify.view. See Migrating from view to viewAsync.
Note: ejs-mate support has been dropped.
Note: marko support has been dropped. Please use @marko/fastify instead.
Benchmarks
The benchmarks were run with the files in the benchmark folder with the ejs engine.
The data has been taken with: autocannon -c 100 -d 5 -p 10 localhost:3000
- Express: 8.8k req/sec
- Fastify: 15.6k req/sec
Install
npm i @fastify/view
Quick start
fastify.register is used to register @fastify/view. By default, It will decorate the reply object with a view method that takes at least two arguments:
- the template to be rendered
- the data that should be available to the template during rendering
This example will render the template using the EJS engine and provide a variable name to be used inside the template:
<!-- index.ejs --->
<!DOCTYPE html>
<html lang="en">
<head></head>
<body>
<p>Hello, <%= name %>!</p>
</body>
</html>
// index.js:
const fastify = require("fastify")()
const fastifyView = require("@fastify/view")
fastify.register(fastifyView, {
engine: {
ejs: require("ejs")
}
})
// synchronous handler:
fastify.get("/", (req, reply) => {
reply.view("index.ejs", { name: "User" });
})
// asynchronous handler:
fastify.get("/", async (req, reply) => {
return reply.viewAsync("index.ejs", { name: "User" });
})
fastify.listen({ port: 3000 }, (err) => {
if (err) throw err;
console.log(`server listening on ${fastify.server.address().port}`);
})
Configuration
Options
| Option | Description | Default |
| ---------------------- | ----------- | ------- |
| engine | Required. The template engine object - pass in the return value of require('<engine>') | |
| production | Enables caching of template files and render functions | NODE_ENV === "production" |
| maxCache | In production mode, maximum number of cached template files and render functions | 100 |
| defaultContext | Template variables available to all views. Variables provided on render have precedence and will override this if they have the same name.
Example: { siteName: "MyAwesomeSite" } | {} |
| propertyName | The property that should be used to decorate reply and fastify
E.g. reply.view() and fastify.view() where "view" is the property name | "view" |
| asyncPropertyName | The property that should be used to decorate reply for async handler
Defaults to ${propertyName}Async if propertyName is defined | "viewAsync" |
| root | The root path of your templates folder. The template name or path passed to the render function will be resolved relative to this path | "./" |
| charset | Default charset used when setting Content-Type header | "utf-8" |
| includeViewExtension | Automatically append the default extension for the used template engine if omitted from the template name. So instead of template.hbs, just template can be used | false |
| viewExt | Override the default extension for a given template engine. This has precedence over includeViewExtension and will lead to the same behavior, just with a custom extension.
Example: "handlebars" | "" |
| layout | See Layouts
This option lets you specify a global layout file to be used when rendering your templates. Settings like root or viewExt apply as for any other template file.
Example: ./templates/layouts/main.hbs | |
| options | See Engine-specific settings | {} |
Example
fastify.register(require("@fastify/view"), {
engine: {
handlebars: require("handlebars"),
},
root: path.join(__dirname, "views"), // Points to `./views` relative to the current file
layout: "./templates/template", // Sets the layout to use to `./views/templates/layout.handlebars` relative to the current file.
viewExt: "handlebars", // Sets the default extension to `.handlebars`
propertyName: "render", // The template can now be rendered via `reply.render()` and `fastify.render()`
defaultContext: {
dev: process.env.NODE_ENV === "development", // Inside your templates, `dev` will be `true` if the expression evaluates to true
},
options: {}, // No options passed to handlebars
});
Layouts
@fastify/view supports layouts for EJS, Handlebars, Eta and doT. When a layout is specified, the request template is first rendered, then the layout template is rendered with the request-rendered html set on body.
Example
<!-- layout.ejs: -->
<!DOCTYPE html>
<html lang="en">
<head></head>
<body>
<!--
Ensure body is not escaped:
EJS: <%- body %>
Handlebars: {{{ body }}}
ETA/doT: <%~ it.body %>
-->
<%- body %>
<br/>
</body>
</html>
<!-- template.ejs: -->
<p><%= text %></p>
// index.js:
fastify.register(fastifyView, {
engine: { ejs },
layout: "layout.ejs"
})
fastify.get('/', (req, reply) => {
const data = { text: "Hello!"}
reply.view('template.ejs', data)
})
Providing a layout on render
Please note: Global layouts and providing layouts on render are mutually exclusive. They can not be mixed.
fastify.get('/', (req, reply) => {
const data = { text: "Hello!"}
reply.view('template.ejs', data, { layout: 'layout.ejs' })
})
Setting request-global variables
Sometimes, several templates should have access to the same request-specific variables. E.g. when setting the current username.
If you want to provide data, which will be depended on by a request and available in all views, you have to add property locals to reply object, like in the example below:
fastify.addHook("preHandler", function (request, reply, done) {
reply.locals = {
text: getTextFromRequest(request), // it will be available in all views
};
done();
});
Properties from reply.locals will override those from defaultContext, but not from data parameter provided to reply.view(template, data) function.
Rendering the template into a variable
The fastify object is decorated the same way as reply and allows you to just render a view into a variable (without request-global variables) instead of sending the result back to the browser:
// Promise based, using async/await
const html = await fastify.view("/templates/index.ejs", { text: "text" });
// Callback based
fastify.view("/templates/index.ejs", { text: "text" }, (err, html) => {
// Handle error
// Do something with `html`
});
If called within a request hook and you need request-global variables, see Migrating from view to viewAsync.
Registering multiple engines
Registering multiple engines with different configurations is supported. They are distinguished via their propertyName:
fastify.register(require("@fastify/view"), {
engine: { ejs: ejs },
layout: "./templates/layout-mobile.ejs",
propertyName: "mobile",
});
fastify.register(require("@fastify/view"), {
engine: { ejs: ejs },
layout: "./templates/layout-desktop.ejs",
propertyName: "desktop",
});
fastify.get("/mobile", (req, reply) => {
// Render using the `mobile` render function
return reply.mobile("/templates/index.ejs", { text: "text" });
});
fastify.get("/desktop", (req, reply) => {
// Render using the `desktop` render function
return reply.desktop("/templates/index.ejs", { text: "text" });
});
Minifying HTML on render
To utilize html-minifier-terser in the rendering process, you can add the option useHtmlMinifier with a reference to html-minifier-terser,
and the optional htmlMinifierOptions option is used to specify the html-minifier-terser options:
// get a reference to html-minifier-terser
const minifier = require('html-minifier-terser')
// optionally defined the html-minifier-terser options
const minifierOpts = {
removeComments: true,
removeCommentsFromCDATA: true,
collapseWhitespace: true,
collapseBooleanAttributes: true,
removeAttributeQuotes: true,
removeEmptyAttributes: true
}
// in template engine options configure the use of html-minifier
options: {
useHtmlMinifier: minifier,
htmlMinifierOptions: minifierOpts
}
To exclude paths from minification, you can add the option pathsToExcludeHtmlMinifier with a list of paths:
// get a reference to html-minifier-terser
const minifier = require('html-minifier-terser')
// in options configure the use of html-minifier-terser and set paths to exclude from minification
const options = {
useHtmlMinifier: minifier,
pathsToExcludeHtmlMinifier: ['/test']
}
fastify.register(require("@fastify/view"), {
engine: {
ejs: require('ejs')
},
options
});
// This path is excluded from minification
fastify.get("/test", (req, reply) => {
reply.view("./template/index.ejs", { text: "text" });
});
Engine-specific settings
Mustache
To use partials in mustache you will need to pass the names and paths in the options parameter:
options: {
partials: {
header: 'header.mustache',
footer: 'footer.mustache'
}
}
fastify.get('/', (req, reply) => {
reply.view('./templates/index.mustache', data)
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.mustache', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
const render = mustache.render.bind(mustache, file)
reply.view(render, data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.mustache', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
Handlebars
To use partials in handlebars you will need to pass the names and paths in the options parameter:
options: {
partials: {
header: 'header.hbs',
footer: 'footer.hbs'
}
}
You can specify compile options as well:
options: {
compileOptions: {
preventIndent: true
}
}
To access defaultContext and reply.locals as @data variables:
options: {
useDataVariables: true
}
To use layouts in handlebars you will need to pass the layout parameter:
fastify.register(require("@fastify/view"), {
engine: {
handlebars: require("handlebars"),
},
layout: "./templates/layout.hbs",
});
fastify.get("/", (req, reply) => {
reply.view("./templates/index.hbs", { text: "text" });
});
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.hbs', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
const render = handlebars.compile(file)
reply.view(render, data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.hbs', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
Nunjucks
You can load templates from multiple paths when using the nunjucks engine:
fastify.register(require("@fastify/view"), {
engine: {
nunjucks: require("nunjucks"),
},
templates: [
"node_modules/shared-components",
"views",
],
});
To configure nunjucks environment after initialization, you can pass callback function to options:
options: {
onConfigure: (env) => {
// do whatever you want on nunjucks env
};
}
fastify.get('/', (req, reply) => {
reply.view('./templates/index.njk', data)
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.njk', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
const render = nunjucks.compile(file)
reply.view(render, data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.njk', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
Liquid
To configure liquid you need to pass the engine instance as engine option:
const { Liquid } = require("liquidjs");
const path = require('node:path');
const engine = new Liquid({
root: path.join(__dirname, "templates"),
extname: ".liquid",
});
fastify.register(require("@fastify/view"), {
engine: {
liquid: engine,
},
});
fastify.get("/", (req, reply) => {
reply.view("./templates/index.liquid", { text: "text" });
});
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.liquid', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
const render = engine.renderFile.bind(engine, './templates/index.liquid')
reply.view(render, data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.liquid', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
doT
When using doT the plugin compiles all templates when the application starts, this way all .def files are loaded and
both .jst and .dot files are loaded as in-memory functions.
This behavior is recommended by the doT team here.
To make it possible it is necessary to provide a root or templates option with the path to the template directory.
fastify.register(require("@fastify/view"), {
engine: {
dot: require("dot"),
},
root: "templates",
options: {
destination: "dot-compiled", // path where compiled .jst files are placed (default = 'out')
},
});
fastify.get("/", (req, reply) => {
// this works both for .jst and .dot files
reply.view("index", { text: "text" });
});
const d = dot.process({ path: 'templates', destination: 'out' })
fastify.get('/', (req, reply) => {
reply.view(d.index, data)
})
fastify.get('/', (req, reply) => {
reply.view({ raw: readFileSync('./templates/index.dot'), imports: { def: readFileSync('./templates/index.def') } }, data)
})
eta
const { Eta } = require('eta')
let eta = new Eta()
fastify.register(pointOfView, {
engine: {
eta
},
templates: 'templates'
})
fastify.get("/", (req, reply) => {
reply.view("index.eta", { text: "text" });
});
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.eta', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view(eta.compile(file), data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.eta', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
ejs
const ejs = require('ejs')
fastify.register(pointOfView, {
engine: {
ejs
},
templates: 'templates'
})
fastify.get("/", (req, reply) => {
reply.view("index.ejs", { text: "text" });
});
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.ejs', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view(ejs.compile(file), data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.ejs', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
pug
const pug = require('pug')
fastify.register(pointOfView, {
engine: {
pug
}
})
fastify.get("/", (req, reply) => {
reply.view("index.pug", { text: "text" });
});
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.pug', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view(pug.compile(file), data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.pug', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
twig
const twig = require('twig')
fastify.register(pointOfView, {
engine: {
twig
}
})
fastify.get("/", (req, reply) => {
reply.view("index.twig", { text: "text" });
});
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.twig', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view(twig.twig({ data: file }), data)
}
})
})
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.twig', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
Miscellaneous
Using @fastify/view as a dependency in a fastify-plugin
To require @fastify/view as a dependency to a fastify-plugin, add the name @fastify/view to the dependencies array in the plugin's opts.
fastify.register(myViewRendererPlugin, {
dependencies: ["@fastify/view"],
});
Forcing a cache-flush
To forcefully clear the cache when in production mode, call the view.clearCache() function.
fastify.view.clearCache();
Migrating from view to viewAsync
The behavior of reply.view is to immediately send the HTML response as soon as rendering is completed, or immediately send a 500 response with error if encountered, short-circuiting fastify's error handling hooks, whereas reply.viewAsync returns a promise that either resolves to the rendered HTML, or rejects on any errors. fastify.view has no mechanism for providing request-global variables, if needed. reply.viewAsync can be used in both sync and async handlers.
Sync handler
Previously:
fastify.get('/', (req, reply) => {
reply.view('index.ejs', { text: 'text' })
})
Now:
fastify.get('/', (req, reply) => {
return reply.viewAsync('index.ejs', { text: 'text' })
})
Async handler
Previously:
// This is an async function
fastify.get("/", async (req, reply) => {
const data = await something();
reply.view("/templates/index.ejs", { data });
return
})
Now:
// This is an async function
fastify.get("/", async (req, reply) => {
const data = await something();
return reply.viewAsync("/templates/index.ejs", { data });
})
fastify.view (when called inside a route hook)
Previously:
// Promise based, using async/await
fastify.get("/", async (req, reply) => {
const html = await fastify.view("/templates/index.ejs", { text: "text" });
return html
})
// Callback based
fastify.get("/", (req, reply) => {
fastify.view("/templates/index.ejs", { text: "text" }, (err, html) => {
if(err) {
reply.send(err)
}
else {
reply.type("application/html").send(html)
}
});
})
Now:
// Promise based, using async/await
fastify.get("/", (req, reply) => {
const html = await fastify.viewAsync("/templates/index.ejs", { text: "text" });
return html
})
fastify.get("/", (req, reply) => {
fastify.viewAsync("/templates/index.ejs", { text: "text" })
.then((html) => reply.type("application/html").send(html))
.catch((err) => reply.send(err))
});
})
Note
By default, views are served with the mime type text/html, with the charset specified in options. You can specify a different Content-Type header using reply.type.
Acknowledgments
This project is kindly sponsored by:
License
Licensed under MIT.