Created by CyanHall.com
on 11/12/2020
, Last updated: 04/30/2021.
πΒ Β
Star me if itβs helpful.
Deno 1.0 is just came out! Let's make a cheatsheet for it!
Read Deno Manual for more details.
πΒ Β
Star me if itβs helpful.
Deno 1.0 is just came out! Let's make a cheatsheet for it!
Read Deno Manual for more details.
1. Installation
curl -fsSL https://deno.land/x/install/install.sh | sh
# or
brew install deno
# upgrade
deno upgrade
# check version
deno -V # deno 1.0.0
deno -help
3. Run Deno script
deno fmt example.js # format source files
deno run example.js # execute a script
# start the REPL
deno
# evaluate code
deno eval "console.log(30933 + 404)" # 31337
5. Allow network access
deno run --allow-net=example.com example.js
# or
deno run --allow-net example.js
7. Command line argument
Deno.args.length
Deno.args[0]
9. Read files
let file = await Deno.open(filename);
await Deno.copy(file, Deno.stdout);
file.close();
11. Execute wasm binaries
# Doc: https://deno.land/manual/getting_started/webassembly
const wasmModule = new WebAssembly.Module(wasmCode);
const wasmInstance = new WebAssembly.Instance(wasmModule);
wasmInstance.exports.main()
13. Multiple threads
// worker.ts
console.log("hello world");
self.close();
// main.ts
new Worker("./worker.ts", { type: "module" });
// shell
deno run --allow-read main.ts # --allow-read permission is required
15. Test asynchronous code
Deno.test("async hello world", async () => {
const x = 1 + 2;
// await some async task
await delay(100);
if (x !== 3) {
throw Error("x should be equal to 3");
}
});
2. Hello World
import { serve } from "https://deno.land/[email protected]/http/server.ts";
const s = serve({ port: 8000 });
console.log("http://localhost:8000/");
for await (const req of s) {
req.respond({ body: "Hello World
" });
}
4. Import third party modules(ES Modules)
import * as log from "https://deno.land/std/log/mod.ts";
6. Allow file access
deno run --allow-read example.js
deno run --allow-write example.js
8. Fetch URL
const res = await fetch(url);
const body = new Uint8Array(await res.arrayBuffer());
await Deno.stdout.write(body);
10. an echo TCP server
const listener = Deno.listen({ port: 8080 });
console.log("listening on 0.0.0.0:8080");
for await (const conn of listener) {
Deno.copy(conn, conn);
}
12. Install a module
deno install --allow-net --allow-read https://deno.land/std/http/file_server.ts
# export PATH="$HOME/.deno/bin:$PATH"
file_server . # serves files in the current directory over HTTP. Just like `python3 -m http.server`
14. Writing tests
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
Deno.test("hello world", () => {
const x = 1 + 2;
assertEquals(x, 3);
});
16. Running tests
deno test # Auto run test match {*_,}test.{js,ts,jsx,tsx} in the current directory (recursively)
# or
deno test my_test.ts
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