Dual Publishing for Deno and Node.js with dnt
Hi I'm Doug
- Senior Frontend Engineer at Skilljar
- He/him
- D&D, Javascript, Soccer, Comics
- Two corgis: Bmo and Mochi
Agenda
- What is Deno?
- Why target Deno?
- Transforming Deno to Node.js with dnt
- Publishing to deno.land and npm
What is Deno?
Deno stands as a secure runtime designed for executing JavaScript and TypeScript.
- Mayank Choubey, The Internals of Deno
What is Deno?
Announced in 2018, and created by Ryan Dahl, the creator of Node.js, Deno is intended to be the successor to Node.js
Dahl's Regrets for Node.js
- Promises
- Open access
- npm
- node_modules
- Implicit require
- index.js
Advantages for Deno
- Sandboxing
- TypeScript Support
- Single Executable
- Third-party packages
- Standard library
Sandboxing
Sandboxing means isolating the environment a program is running in so that it cannot affect the system or platform it is running on.
Sandboxing: Node.js
Node.js has added sandboxing behind a flag as of version 20 (now lts!)
1node --experimental-permission --allow-fs-read=* --allow-fs-write=* index.jsSandboxing: Deno
When running programs using Deno, we have to explicity grant permissions.
1deno --allow-read --allow-env --allow-net mod.tsTypeScript
TypeScript is a superset of JavaScript that adds type safety. It catches errors at build time instead of run time.
Deno supports TypeScript out-of-the-box.
TypeScript: Node.js
- Install TypeScript
- Create a tsconfig
- Configure compile and watch scripts
- Create your file
- Compile your file
- Run your file
TypeScript: Deno
- Create your file
- Run your file
Single Executable
Deno has a suite of development tools bundled into a single toolkit. This makes it easier to configure projects and keep consistency across the community.
Single Executable: Node.js v Deno
- node
- node inspect
- deno
- deno bench
- deno bundle
- deno coverage
- deno fmt
- deno lint
- deno test
- and more!
Single Executable: Deno
1name: Deno
2
3on:
4 push:
5 branches: ["main"]
6 pull_request:
7 branches: ["main"]
8
9permissions:
10 contents: read
11
12jobs:
13 test:
14 runs-on: ubuntu-latest
15
16 steps:
17 - name: Setup repo
18 uses: actions/checkout@v3
19
20 - name: Setup Deno
21 uses: denoland/setup-deno@v1
22 with:
23 deno-version: v1.x
24
25 - name: Verify formatting
26 run: deno fmt --check
27
28 - name: Run linter
29 run: deno lint
30
31 - name: Run tests
32 run: deno test --ignore=npm
33
34 - name: Run npm build
35 run: deno task npm-buildStandard Library
Deno has a much larger standard library than Node.js that is actively maintained by the Deno team.
The standard library is installed separately from the cli and is heavily inspired by Go.
Examples of stdlib additions
- uuid
- fetch
- yaml
- jsonc
- dotenv
Standard Library: Deno
1// import from the standard library
2 import { assert } from "https://deno.land/std@0.205.0/assert/mod.ts";
3 import { parse } from "https://deno.land/std@0.205.0/flags/mod.ts";Third-party packages
Deno doesn't use npm or pnpm or yarn to manage third-party dependencies.
Third-party packages
Node.js
- npm
- git urls
- local paths
- tarball urls
Deno
- npm
- git urls
- local paths
- deno land
Third-party packages: Deno
1// import from a deno land package
2 import cliui from "https://deno.land/x/cliui@v8.0.1-deno/deno.ts";
3
4 // import from an npm package
5 import itscalledsoccer from "npm:/itscalledsoccer/";Except!
There's like, way more code and developers in the Node.js/npm ecosystem!
What if we could have the benefits of developing for Deno while also supporting Node.js?
dnt - Deno to Node.js Transform
Takes a Deno module and creates an npm package for use in Node.js
dnt steps
- Builds esm and cjs targets
- Type checks the npm package
- Emits TypeScript declaration files
- Runs the tests against the generated code
Build script
1import { build, emptyDir } from "https://deno.land/x/dnt@0.38.1/mod.ts";
2
3const firstArg = Deno.args[0] || "v0.0.1";
4
5const version = firstArg.startsWith("v") ? firstArg.replace("v", "") : firstArg;
6
7console.log(`building version ${version}`);
8
9await emptyDir("./npm");
10
11await build({
12 entryPoints: [{
13 kind: "bin",
14 name: "lemmyscorecard",
15 path: "./mod.ts",
16 }],
17 outDir: "./npm",
18 package: {
19 name: "lemmyscorecard",
20 version,
21 description: "Gets the total post and comment karma for a Lemmy user.",
22 license: "MIT",
23 repository: {
24 type: "git",
25 url: "git+https://github.com/doug-wade/lemmy-scorecard.git",
26 },
27 bugs: {
28 url: "https://github.com/doug-wade/lemmy-scorecard/issues",
29 },
30 },
31 mappings: {
32 "npm:/lemmy-js-client/": {
33 name: "lemmy-js-client",
34 version: "^0.18.0",
35 },
36 },
37 postBuild() {
38 Deno.copyFileSync("LICENSE", "npm/LICENSE");
39 Deno.copyFileSync("README.md", "npm/README.md");
40 },
41 shims: {
42 deno: true,
43 },
44});Shims
1import main from "./main.ts";
2 main(Deno.args);Becomes
1import "./_dnt.polyfills.js";
2 import * as dntShim from "./_dnt.shims.js";
3 import main from "./main.js";
4
5 main(dntShim.Deno.args);Shims
1» ls node_modules/lemmyscorecard/esm/deps/deno.land/std@0.205.0/assert/
2_constants.d.ts assert_false.d.ts assert_not_equals.d.ts assert_throws.d.ts
3_constants.js assert_false.js assert_not_equals.js assert_throws.js
4_diff.d.ts assert_greater.d.ts assert_not_instance_of.d.ts assertion_error.d.ts
5_diff.js assert_greater.js assert_not_instance_of.js assertion_error.js
6_format.d.ts assert_greater_or_equal.d.ts assert_not_match.d.ts equal.d.ts
7_format.js assert_greater_or_equal.js assert_not_match.js equal.js
8assert.d.ts assert_instance_of.d.ts assert_not_strict_equals.d.ts fail.d.ts
9assert.js assert_instance_of.js assert_not_strict_equals.js fail.js
10assert_almost_equals.d.ts assert_is_error.d.ts assert_object_match.d.ts mod.d.ts
11assert_almost_equals.js assert_is_error.js assert_object_match.js mod.js
12assert_array_includes.d.ts assert_less.d.ts assert_rejects.d.ts unimplemented.d.ts
13assert_array_includes.js assert_less.js assert_rejects.js unimplemented.js
14assert_equals.d.ts assert_less_or_equal.d.ts assert_strict_equals.d.ts unreachable.d.ts
15assert_equals.js assert_less_or_equal.js assert_strict_equals.js unreachable.js
16assert_exists.d.ts assert_match.d.ts assert_string_includes.d.ts
17assert_exists.js assert_match.js assert_string_includes.jsBuild example
1» deno task npm-build 1 ↵
2Task npm-build deno run --allow-env --allow-read --allow-net --allow-write --allow-run npm-build.ts
3building version 0.0.1
4[dnt] Transforming...
5[dnt] Running npm install...
6
7added 19 packages, and audited 20 packages in 2s
8
9found 0 vulnerabilities
10[dnt] Building project...
11[dnt] Type checking ESM...
12[dnt] Emitting ESM package...
13[dnt] Emitting script package...
14[dnt] Type checking script...
15[dnt] Running post build action...
16[dnt] Running tests...
17
18> lemmyscorecard@0.0.1 test
19> node test_runner.js
20
21Running tests in ./script/main.test.js...
22
23test main ...lemmy-scorecard v0.0.4
24usage: deno run lemmy-scorecard --username <my username> --instance <my instance url>
25
26 test outputs the version ... ok
27 test outputs a help message ... ok
28 test outputs an error message when called with no args ... ok
29ok
30
31Running tests in ./esm/main.test.js...
32
33test main ...lemmy-scorecard v0.0.4
34usage: deno run lemmy-scorecard --username <my username> --instance <my instance url>
35
36 test outputs the version ... ok
37 test outputs a help message ... ok
38 test outputs an error message when called with no args ... ok
39ok
40[dnt] Complete!Unit test example
1» deno task npm-build
2Task npm-build deno run --allow-env --allow-read --allow-net --allow-write --allow-run npm-build.ts
3A new release of Deno is available: 1.37.2 → 1.38.0 Run `deno upgrade` to install it.
4building version 0.0.1
5[dnt] Transforming...
6[dnt] Running npm install...
7
8added 19 packages, and audited 20 packages in 2s
9
10found 0 vulnerabilities
11[dnt] Building project...
12[dnt] Type checking ESM...
13[dnt] Emitting ESM package...
14[dnt] Emitting script package...
15[dnt] Type checking script...
16[dnt] Running post build action...
17[dnt] Running tests...
18
19> lemmyscorecard@0.0.1 test
20> node test_runner.js
21
22Running tests in ./script/main.test.js...
23
24test main ...lemmy-scorecard v0.0.4
25usage: deno run lemmy-scorecard --username <my username> --instance <my instance url>
26
27 test outputs the version ...
28 AssertionError: spy not called with expected args:
29
30
31 [Diff] Actual / Expected
32
33
34 [
35 - 'lemmy-scorecard v0.0.4'
36 + 'lemmy-scorecard v0.0.5'
37 ]
38
39 at assertSpyCall (/Users/doug/code/lemmy-scorecard/npm/script/deps/deno.land/std@0.205.0/testing/mock.js:582:23)
40 at Object.<anonymous> (/Users/doug/code/lemmy-scorecard/npm/script/main.test.js:20:37)
41 at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
42 at async TestSuiteInternal.runTest (/Users/doug/code/lemmy-scorecard/npm/script/deps/deno.land/std@0.205.0/testing/_test_suite.js:307:13)
43 at async TestSuiteInternal.runTest (/Users/doug/code/lemmy-scorecard/npm/script/deps/deno.land/std@0.205.0/testing/_test_suite.js:292:17)
44 at async Object.fn (/Users/doug/code/lemmy-scorecard/npm/script/deps/deno.land/std@0.205.0/testing/_test_suite.js:265:25)
45 at async Object.step (/Users/doug/code/lemmy-scorecard/npm/test_runner.js:136:21)
46 at async TestSuiteInternal.run (/Users/doug/code/lemmy-scorecard/npm/script/deps/deno.land/std@0.205.0/testing/_test_suite.js:273:13)
47 at async Object.fn (/Users/doug/code/lemmy-scorecard/npm/script/deps/deno.land/std@0.205.0/testing/_test_suite.js:130:29)
48 at async runTestDefinitions (/Users/doug/code/lemmy-scorecard/npm/test_runner.js:54:13)
49 fail
50 test outputs a help message ... ok
51 test outputs an error message when called with no args ... ok
52fail
53
54FAILURES
55
56main
57 Error: Had failing test step.
58 at runTestDefinitions (/Users/doug/code/lemmy-scorecard/npm/test_runner.js:58:26)
59 at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
60 at async main (/Users/doug/code/lemmy-scorecard/npm/test_runner.js:31:9)error: Uncaught (in promise) Error: npm run test failed with exit code 1
61 throw new Error(
62 ^
63 at runCommand (https://deno.land/x/dnt@0.38.1/lib/utils.ts:56:13)
64 at eventLoopTick (ext:core/01_core.js:183:11)
65 at async build (https://deno.land/x/dnt@0.38.1/mod.ts:407:5)
66 at async file:///Users/doug/code/lemmy-scorecard/npm-build.ts:11:1Type check example
1» deno task npm-build 1 ↵
2Task npm-build deno run --allow-env --allow-read --allow-net --allow-write --allow-run npm-build.ts
3building version 0.0.1
4[dnt] Transforming...
5[dnt] Running npm install...
6
7added 19 packages, and audited 20 packages in 484ms
8
9found 0 vulnerabilities
10[dnt] Building project...
11[dnt] Type checking ESM...
12src/main.ts:71:46 - error TS2322: Type 'number' is not assignable to type 'string'.
13
1471 const scorecard = await fetchDataForUser({ username: 1, instance: 2 });
15 ~~~~~~~~
16
17 src/main.ts:27:5
18 27 username: string;
19 ~~~~~~~~
20 The expected type comes from property 'username' which is declared here on type '{ instance: string; username: string; }'
21src/main.ts:71:59 - error TS2322: Type 'number' is not assignable to type 'string'.
22
2371 const scorecard = await fetchDataForUser({ username: 1, instance: 2 });
24 ~~~~~~~~
25
26 src/main.ts:26:5
27 26 instance: string;
28 ~~~~~~~~
29 The expected type comes from property 'instance' which is declared here on type '{ instance: string; username: string; }'
30
31error: Uncaught (in promise) Error: Had 2 diagnostics.
32 throw new Error(`Had ${diagnostics.length} diagnostics.`);
33 ^
34 at getProgramAndMaybeTypeCheck (https://deno.land/x/dnt@0.38.1/mod.ts:456:17)
35 at build (https://deno.land/x/dnt@0.38.1/mod.ts:345:17)
36 at eventLoopTick (ext:core/01_core.js:183:11)
37 at async file:///Users/doug/code/lemmy-scorecard/npm-build.ts:11:1Publishing to npm
The resulting, generated package can be published to npm using the npm cli, so however you publish your npm packages today should work.
Publishing to Deno
Deno modules are published to deno.land/x via a GitHub webhook.
Publishing to Deno
Deno will also fetch code directly from github via import
1import main from 'https://raw.githubusercontent.com/doug-wade/lemmy-scorecard/main/main.ts';
2
3 await main(Deno.args);Publishing script
1# This workflow will run tests using node and then publish a package to GitHub Packages when a release is created
2# For more information see: https://docs.github.com/en/actions/publishing-packages/publishing-nodejs-packages
3
4name: Node.js Package
5
6on:
7 release:
8 types: [created]
9
10jobs:
11 build:
12 runs-on: ubuntu-latest
13 steps:
14 - name: Get tag version
15 if: startsWith(github.ref, 'refs/tags/')
16 id: get_tag_version
17 run: echo "TAG_VERSION=${GITHUB_REF/refs\/tags\//}" >> "$GITHUB_ENV"
18
19 - name: Setup repo
20 uses: actions/checkout@v3
21
22 - name: Setup deno
23 uses: denoland/setup-deno@v1
24 with:
25 deno-version: v1.x
26
27 - uses: actions/setup-node@v3
28 with:
29 node-version: 20
30 registry-url: https://registry.npmjs.org/
31
32 - name: Build npm package
33 run: deno task npm-build $TAG_VERSION
34
35 - name: Publish npm package
36 working-directory: ./npm
37 run: npm publish
38 env:
39 NODE_AUTH_TOKEN: ${{secrets.npm_token}}Publishing demo
Pull requestQuestions?
