Just yesterday, Node.js v18 was released as the current stable version. Here's a quick walkthrough of some of the new features.
Global fetch!
Node.js had a global fetch behind the --experimental-fetch
flag, which would allow you to use the Browser Fetch API natively in Node.js. In v18, the experimental Fetch API is available by default.
fetch('https://jsonplaceholder.typicode.com/todos/1')
.then(response => response.json())
.then(json => console.log(json))
(node:82823) ExperimentalWarning: The Fetch API is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
{ userId: 1, id: 1, title: 'delectus aut autem', completed: false }
You also get access to FormData
, Headers
, Request
, and Response
objects.
Access to the Web Streaming API
Node.js now has experimental support for the Web Streaming API
fetch('https://dev.to/api/articles?per_page=1000&page=1')
.then(response => response.body)
.then(rb => rb.getReader())
.then(reader => {
const stream = new ReadableStream({
...
})
})
Built in testing
Node.js now has a built-in testing framework, accesible at import('node:test')
import test from 'node:test';
import assert from 'node:assert';
test('true is not false', async t => {
assert.strictEqual(true, !false);
});
$ node test.js
(node:83584) ExperimentalWarning: The test runner is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
TAP version 13
ok 1 - true is not false
---
duration_ms: 0.000730654
...
1..1
# tests 1
# pass 1
# fail 0
# skipped 0
# todo 0
# duration_ms 0.074570679
The output is in the TAP format. You can use the tap
or faucet
CLIs to pretty print it
$ npm i -g tap
$ tap test.js
index.js 2> (node:84725) ExperimentalWarning: The test runner is an experimental feature. This feature could change at any time
index.js 2> (Use `node --trace-warnings ...` to show where the warning was created)
PASS index.js 1 OK 239.361ms
🌈 SUMMARY RESULTS 🌈
Suites: 1 passed, 1 of 1 completed
Asserts: 1 passed, of 1
Time: 415.463ms
----------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------|---------|----------|---------|---------|-------------------
All files | 0 | 0 | 0 | 0 |
----------|---------|----------|---------|---------|-------------------
$ npm i -g faucet
$ node test.js | faucet
(node:84914) ExperimentalWarning: The test runner is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
✓ true is not false
# tests 1
# pass 1
✓ skipped 0
✓ todo 0
✓ duration_ms 0.076367098
You can read the documentation to learn more
Binaries!
Users can now build Node.js with custom V8 startup snapshots, to increase performance.
In layman's terms, this means that you can cache some dependencies in the node.js source code itself, to improve startup time.
$ cd /where/is/node/source/code
$ ./configure --node-snapshot-main=marked.js # where marked.js is the source of the marked library
$ make node
// your-program.js
// globalThis.marked is now deserialized from the snapshot
// so node.js doesnt need to parse it again
// which improves startup time
const marked = globalThis.marked;
marked(/* ... */);
$ out/Release/node your-program.js
Node.js is working on JS APIs for this, which means that we can essentially build Node.js apps as distributable binaries!
Node.js v18 has some really exciting new features. I've been waiting forever for the fetch API to land and I've always wished Node.js had binaries. The testing framework is also neat!
Top comments (1)
Thanks for this article. I think these new features can be useful in general!