@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" });
});
Rendering a template from a string ("raw" template)
The reply.view({ raw }) option allows you to render a template from a string instead of a file. This is useful when you want to render a template that is not stored in a file, or when you want to use a template that is generated dynamically.
fastify.get('/', (req, reply) => {
fs.readFile('./templates/index.mustache', 'utf8', (err, file) => {
if (err) {
reply.send(err)
} else {
reply.view({ raw: file }, data)
}
})
})
Note that by using the raw option, you are considering the template as trusted - @fastify/view does not perform any
validation on the template content.
DO NOT USE raw with untrusted content, or you will make yourself vulnerable to Remote Code Execution (RCE) attacks.
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)
}
})
})
Edge
const { Edge } = require('edge.js')
const { join } = require('node:path')
const engine = new Edge()
engine.mount(join(__dirname, '..', 'templates'))
fastify.register(require('../index'), {
engine: {
edge: engine
}
})
fastify.get('/', (_req, reply) => {
reply.view('index.edge', 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.
