Generate html in the most natural Fastify way, using template tags, layouts and the plugin system.
Template expressions are escaped by default unless they are prefixed with !.
npm i fastify fastify-htmlimport fastify from 'fastify'
import fastifyHtml from 'fastify-html'
const app = fastify()
await app.register(fastifyHtml)
app.addLayout(function (inner, reply) {
return app.html`
<!DOCTYPE html>
<html lang="en">
<head>
<script src="https://unpkg.com/[email protected]"></script>
</head>
<body>
<!-- Prefix expressions with ! if they contain safe HTML or other html tags -->
!${inner}
</body>
</html>
`
}, { skipOnHeader: 'hx-request' })
app.get('/', async (req, reply) => {
const name = req.query.name || 'World'
return reply.html`<h1>Hello ${name}</h1>`
})
app.get('/complex-response/:page', async (req, reply) => {
const name = req.query.name || 'World'
const userInfo = await getUserInfo(name) || {}
const demand = req.query.demand
return reply.html`
<div>
Welcome, ${name}.
<br /><br />
User information:
<br />
!${Object.keys(userInfo).map(
(key) => app.html`
${key}: <b>${userInfo[key]}</b>
<br />
`
)}
<br />
!${
demand
? app.html`
<p>Your demand: ${demand}</p>
`
: ""
}
</div>
`
})
await app.listen({ port: 3000 })
async function getUserInfo(name) {
return { age: 25, location: "Earth" };
}import fastify from 'fastify'
import fastifyHtml from 'fastify-html'
import { createReadStream } from 'node:fs'
const app = fastify()
await app.register(fastifyHtml, { async: true })
app.addLayout(function (inner, reply) {
return app.html`
<!DOCTYPE html>
<html lang="en">
<head>
<script src="https://unpkg.com/[email protected]"></script>
</head>
<body>
!${inner}
</body>
</html>
`
}, { skipOnHeader: 'hx-request' })
app.get('/:name', async (req, reply) => {
return reply.html`
<div>
Welcome, ${req.params.name}.
<br /><br />
User information:
<br />
<!-- Promises are supported and resolved automatically in async mode -->
!${getUserInfoPromise(req.params.name)}
<br />
<!-- Streams and (a)sync generators are supported too -->
<div>
File content:
<br />
!${createReadStream('./path/to/file.txt')}
</div>
</div>
`
})
await app.listen({ port: 3000 })
async function getUserInfoPromise(name) {
return new Promise((resolve) => {
setTimeout(() => {
resolve({ age: 25, location: "Earth" });
}, 1000);
});
}Encapsulation is supported and respected for layouts, meaning that addLayout
calls will be not exposed to the parent plugin, like the following:
import fastify from 'fastify'
import fastifyHtml from 'fastify-html'
const app = fastify()
await app.register(fastifyHtml)
app.addLayout(function (inner, reply) {
return app.html`
<!DOCTYPE html>
<html lang="en">
<body>
!${inner}
</body>
</html>
`
})
app.get('/', async (req, reply) => {
const name = req.query.name || 'World'
strictEqual(reply.html`<h1>Hello ${name}</h1>`, reply)
return reply
})
app.register(async function (app) {
app.addLayout(function (inner) {
return app.html`
<i>
!${inner}
</i>
`
})
app.get('/nested', async (req, reply) => {
const name = req.query.name || 'World'
return reply.html`<h1>Nested ${name}</h1>`
})
})
await app.listen({ port: 3000 })async: Enables async mode for handling asynchronous template expressions. Set this option to true when registering the fastify-html plugin to take advantage of features like promise resolution, stream handling, and async generator support.
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