Suggest adding type field

closes #83
bluwy · Dec 23, 2023 · a0e16e8 · a0e16e8
1 parent 16facaa
commit a0e16e8
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Showing 24 changed files with 43 additions and 2 deletions.
diff --git a/pkg/index.d.ts b/pkg/index.d.ts
@@ -70,6 +70,7 @@ export type Message =
   | BaseMessage<'USE_EXPORTS_BROWSER'>
   | BaseMessage<'USE_EXPORTS_OR_IMPORTS_BROWSER'>
   | BaseMessage<'USE_FILES'>
+  | BaseMessage<'USE_TYPE'>
   | BaseMessage<
       'TYPES_NOT_EXPORTED',
       {

diff --git a/pkg/src/index.js b/pkg/src/index.js
@@ -76,6 +76,17 @@ export async function publint({ pkgDir, vfs, level, strict, _packedFiles }) {
     })
   }
 
+  // Check if "type" field is specified, help Node.js push towards an ESM default future:
+  // https://nodejs.org/en/blog/release/v20.10.0
+  if (rootPkg.type == null) {
+    messages.push({
+      code: 'USE_TYPE',
+      args: {},
+      path: ['name'],
+      type: 'suggestion'
+    })
+  }
+
   // Relies on default node resolution
   // https://nodejs.org/api/modules.html#all-together
   // LOAD_INDEX(X)

diff --git a/pkg/src/message.js b/pkg/src/message.js
@@ -98,6 +98,9 @@ export function formatMessage(m, pkg) {
     case 'USE_FILES':
       // prettier-ignore
       return `The package ${c.bold('publishes internal tests or config files')}. You can use ${c.bold('pkg.files')} to only publish certain files and save user bandwidth.`
+    case 'USE_TYPE':
+      // prettier-ignore
+      return `The package does not specify the ${c.bold('type')} field. Environments may incorrectly identify a CJS file as ESM in the future. Consider adding ${c.bold('"type"')}: "${c.bold('commonjs')}".`
     case 'TYPES_NOT_EXPORTED': {
       const typesFilePath = exportsRel(m.args.typesFilePath)
       if (m.args.actualExtension && m.args.expectExtension) {

diff --git a/pkg/tests/fixtures/exports-browser-conflict/package.json b/pkg/tests/fixtures/exports-browser-conflict/package.json
@@ -2,6 +2,7 @@
   "name": "publint-exports-browser-conflict",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "browser": {
     "./lib.server.js": "./lib.browser.js"
   },

diff --git a/pkg/tests/fixtures/exports-module/package.json b/pkg/tests/fixtures/exports-module/package.json
@@ -2,6 +2,7 @@
   "name": "publint-exports-module",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "exports": {
     ".": {
       "import": "./main.mjs",

diff --git a/pkg/tests/fixtures/exports-styles/package.json b/pkg/tests/fixtures/exports-styles/package.json
@@ -2,6 +2,7 @@
   "name": "publint-exports-styles",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "exports": {
     "./array": {
       "import": ["./array.js", "./non-existent.js", "std:lib"]

diff --git a/pkg/tests/fixtures/glob-deprecated/package.json b/pkg/tests/fixtures/glob-deprecated/package.json
@@ -2,6 +2,7 @@
   "name": "publint-glob-deprecated",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "exports": {
     "./": "./src/"
   }

diff --git a/pkg/tests/fixtures/glob/package.json b/pkg/tests/fixtures/glob/package.json
@@ -1,5 +1,6 @@
 {
   "name": "publint-glob",
   "version": "0.0.1",
-  "private": true
+  "private": true,
+  "type": "commonjs"
 }
diff --git a/pkg/tests/fixtures/invalid-field-types/package.json b/pkg/tests/fixtures/invalid-field-types/package.json
@@ -2,6 +2,7 @@
   "name": "publint-invalid-field-types",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "main": 0,
   "module": true,
   "jsnext:main": false

diff --git a/pkg/tests/fixtures/invalid-jsx-extensions/package.json b/pkg/tests/fixtures/invalid-jsx-extensions/package.json
@@ -2,6 +2,7 @@
   "name": "publint-invalid-jsx-extensions",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "main": "./main.cjsx",
   "module": "./main.mjsx"
 }
diff --git a/pkg/tests/fixtures/missing-files/package.json b/pkg/tests/fixtures/missing-files/package.json
@@ -2,6 +2,7 @@
   "name": "publint-missing-files",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "main": "missing.js",
   "jsnext:main": "./missing.js",
   "jsnext": "./missing.js",

diff --git a/pkg/tests/fixtures/not-missing-files/package.json b/pkg/tests/fixtures/not-missing-files/package.json
@@ -2,5 +2,6 @@
   "name": "publint-not-missing-files",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "main": "index"
 }
diff --git a/pkg/tests/fixtures/publish-config/package.json b/pkg/tests/fixtures/publish-config/package.json
@@ -2,6 +2,7 @@
   "name": "publint-publish-config",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "main": "missing.js",
   "browser": "missing.js",
   "exports": {

diff --git a/pkg/tests/fixtures/test-1/package.json b/pkg/tests/fixtures/test-1/package.json
@@ -2,5 +2,6 @@
   "name": "publint-test-1",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "exports": "./main.js"
 }
diff --git a/pkg/tests/fixtures/test-2/package.json b/pkg/tests/fixtures/test-2/package.json
@@ -2,6 +2,7 @@
   "name": "publint-test-2",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "main": "./main.mjs",
   "browser": "./lib/bar.js",
   "typings": "./doesn't-exist.d.ts",

diff --git a/pkg/tests/fixtures/types-exports-resolution-cjs/package.json b/pkg/tests/fixtures/types-exports-resolution-cjs/package.json
@@ -2,6 +2,7 @@
   "name": "publint-types-exports-resolution-cjs",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "types": "./main.d.ts",
   "exports": {
     ".": {

diff --git a/pkg/tests/fixtures/types-exports-resolution-dual-explicit/package.json b/pkg/tests/fixtures/types-exports-resolution-dual-explicit/package.json
@@ -2,6 +2,7 @@
   "name": "publint-types-exports-resolution-dual-explicit",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "types": "./main-special.d.ts",
   "exports": {
     ".": {

diff --git a/pkg/tests/fixtures/types-exports-resolution-dual/package.json b/pkg/tests/fixtures/types-exports-resolution-dual/package.json
@@ -2,6 +2,7 @@
   "name": "publint-types-exports-resolution-dual",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "types": "./main-special.d.ts",
   "exports": {
     ".": {

diff --git a/pkg/tests/fixtures/types-exports-resolution/package.json b/pkg/tests/fixtures/types-exports-resolution/package.json
@@ -2,6 +2,7 @@
   "name": "publint-types-exports-resolution",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "types": "./main.d.ts",
   "exports": {
     ".": {

diff --git a/pkg/tests/fixtures/types-versions/package.json b/pkg/tests/fixtures/types-versions/package.json
@@ -2,6 +2,7 @@
   "name": "publint-types-versions",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "types": "./main.d.ts",
   "typesVersions": {}
 }
diff --git a/pkg/tests/fixtures/types/package.json b/pkg/tests/fixtures/types/package.json
@@ -2,6 +2,7 @@
   "name": "publint-types",
   "version": "0.0.1",
   "private": true,
+  "type": "commonjs",
   "types": "./main.d.ts",
   "exports": {
     ".": {

diff --git a/pkg/tests/playground.js b/pkg/tests/playground.js
@@ -140,7 +140,8 @@ testFixture('umd', ['FILE_INVALID_FORMAT', 'FILE_INVALID_FORMAT'])
 
 testFixture('deprecated-fields', [
   'DEPRECATED_FIELD_JSNEXT',
-  'DEPRECATED_FIELD_JSNEXT'
+  'DEPRECATED_FIELD_JSNEXT',
+  'USE_TYPE'
 ])
 
 /**

diff --git a/site/rules.md b/site/rules.md
@@ -202,6 +202,10 @@ Internal tests or config files are published, which are usually not needed and u
 }
 ```
 
+## `USE_TYPE`
+
+Since [Node.js v20.10.0](https://nodejs.org/en/blog/release/v20.10.0), it introduces a new `--experimental-default-type` flag to flip the default module system from "CJS-as-default" to "ESM-as-default". If enabled, `package.json` without the `"type"` field will mean its descendant JS files to be interpreted as ESM instead of CJS, which may not work correctly. Hence, if you've not set the `"type"` field, it's recommended to set as `"type": "commonjs"` (default value) to be future-proof.
+
 ## `FIELD_INVALID_VALUE_TYPE`
 
 Some `package.json` fields has a set of allowed types, e.g. `string` or `object` only. If an invalid type is passed, this error message will be showed.

diff --git a/site/src/utils/message.js b/site/src/utils/message.js
@@ -92,6 +92,9 @@ function messageToString(m, pkg) {
     case 'USE_FILES':
       // prettier-ignore
       return `The package ${bold('publishes internal tests or config files')}. You can use ${bold('pkg.files')} to only publish certain files and save user bandwidth.`
+    case 'USE_TYPE':
+      // prettier-ignore
+      return `The package does not specify the ${bold('"type"')} field. Environments may incorrectly identify a CJS file as ESM in the future. Consider adding ${bold('"type"')}: "${bold('commonjs')}".`
     case 'TYPES_NOT_EXPORTED': {
       const typesFilePath = exportsRel(m.args.typesFilePath)
       if (m.args.actualExtension && m.args.expectExtension) {