Run typescript in custom codegen script

common/changes/eslint-plugin-codegen/codegen-debug-custom_pr-228.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "comment": "Run typescript in custom codegen script (#228)",
+      "type": "minor",
+      "packageName": "eslint-plugin-codegen"
+    }
+  ],
+  "packageName": "eslint-plugin-codegen",
+  "email": "mmkal@users.noreply.github.com"
+}

packages/eslint-plugin-codegen/.eslintrc.js

@@ -1 +1,8 @@
-module.exports = require('@mmkal/rig/.eslintrc')
+const base = require('@mmkal/rig/.eslintrc')
+module.exports = {
+  ...base,
+  ignorePatterns: [
+    ...base.ignorePatterns,
+    '**/__tests__/custom-preset.js',
+  ],
+}

packages/eslint-plugin-codegen/package.json

@@ -62,6 +62,7 @@
     "expect-type": "workspace:*",
     "minimatch": "3.0.4",
     "read-pkg-up": "7.0.1",
-    "eslint": "7.15.0"
+    "eslint": "7.15.0",
+    "ts-node": "9.1.1"
   }
 }

packages/eslint-plugin-codegen/readme.md

@@ -259,7 +259,7 @@ Generates a yaml config for the [GitHub Pull Request Labeler Action](https://git
 
 
 <!-- codegen:start {preset: markdownFromJsdoc, source: src/presets/custom.ts, export: custom} -->
-#### [custom](./src/presets/custom.ts#L26)
+#### [custom](./src/presets/custom.ts#L28)
 
 Define your own codegen function, which will receive all options specified. Import the `Preset` type from this library to define a strongly-typed preset function:
 
@@ -279,10 +279,12 @@ This can be used with:
 
 ##### Params
 
-|name  |description                                                                       |
-|------|----------------------------------------------------------------------------------|
-|source|Relative path to the module containing the custom preset                          |
-|export|The name of the export. If omitted, the module itself should be a preset function.|
+|name   |description                                                                                                                       |
+|-------|----------------------------------------------------------------------------------------------------------------------------------|
+|source |Relative path to the module containing the custom preset.                                                                         |
+|export |The name of the export. If omitted, the module itself should be a preset function.                                                |
+|require|A module to load before `source`. If not set, defaults to `ts-node/register/transpile-only` for typescript sources.               |
+|dev    |Set to `true` to clear the require cache for `source` before loading. Allows editing the function without requiring an IDE reload.|
 <!-- codegen:end -->
 
 ##### Demo

packages/eslint-plugin-codegen/src/index.ts

@@ -6,6 +6,9 @@ import * as eslint from 'eslint'
 import * as presetsModule from './presets'
 import expect from 'expect'
 
+// todo: run prettier on output, if found
+// todo: codegen/fs rule. type fs.anything and it generates an import for fs. same for path and os.
+
 type MatchAll = (text: string, pattern: string | RegExp) => Iterable<NonNullable<ReturnType<string['match']>>>
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const matchAll: MatchAll = require('string.prototype.matchall')

packages/eslint-plugin-codegen/src/presets/__tests__/custom-preset.ts

@@ -0,0 +1 @@
+export const getText = () => 'typescript text'

packages/eslint-plugin-codegen/src/presets/__tests__/custom.test.ts

@@ -1,45 +1,103 @@
 import * as preset from '../custom'
+import * as path from 'path'
 
-test('loads custom export', () => {
+jest.mock('ts-node/register/transpile-only')
+
+test('custom preset validation', () => {
   // eslint-disable-next-line @typescript-eslint/no-var-requires
   const customPreset = require('./custom-preset')
 
   expect(Object.keys(customPreset)).toEqual(['getText', 'thrower'])
 
   expect(customPreset.getText.toString().trim()).toMatch(/'Named export with input: ' \+ options.input/)
+})
 
+test('named export', () => {
   expect(
     preset.custom({
       meta: {filename: __filename, existingContent: ''},
       options: {source: './custom-preset.js', export: 'getText', input: 'abc'},
     })
   ).toMatchInlineSnapshot(`"Named export with input: abc"`)
+})
 
+test('whole module export', () => {
   expect(
     preset.custom({
       meta: {filename: __filename, existingContent: ''},
       options: {source: './custom-preset.js', input: 'def'},
     })
   ).toMatchInlineSnapshot(`"Whole module export with input: def"`)
+})
+
+test('load typescript with ts-node', () => {
+  expect(
+    preset.custom({
+      meta: {filename: __filename, existingContent: ''},
+      options: {source: './custom-preset.ts', export: 'getText'},
+    })
+  ).toMatchInlineSnapshot(`"typescript text"`)
+})
 
+test('dev mode, deletes require cache', () => {
+  expect(
+    preset.custom({
+      meta: {filename: __filename, existingContent: ''},
+      options: {source: './custom-preset.js', input: 'ghi', dev: true},
+    })
+  ).toMatchInlineSnapshot(`"Whole module export with input: ghi"`)
+})
+
+test(`when source isn't specified, uses filename`, () => {
+  expect(
+    preset.custom({
+      meta: {filename: path.join(__dirname, 'custom-preset.js'), existingContent: ''},
+      options: {input: 'abc'},
+    })
+  ).toEqual('Whole module export with input: abc')
+})
+
+test('errors for non-existent source file', () => {
   expect(() =>
     preset.custom({
       meta: {filename: __filename, existingContent: ''},
-      options: {source: './does-not-exist.ts', export: 'getText', input: 'abc'},
+      options: {source: './does-not-exist.ts'},
     })
-  ).toThrowError(/Source path doesn't exist: .*does-not-exist.ts/)
+  ).toThrowError(/Source path is not a file: .*does-not-exist.ts/)
+})
 
+test('errors if directory passed as source', () => {
+  expect(() =>
+    preset.custom({
+      meta: {filename: __filename, existingContent: ''},
+      options: {source: '__tests__'},
+    })
+  ).toThrowError(/Source path is not a file: .*__tests__/)
+})
+
+test('errors for non-existent export', () => {
   expect(() =>
     preset.custom({
       meta: {filename: __filename, existingContent: ''},
       options: {source: './custom-preset.js', export: 'doesNotExist', input: 'abc'},
     })
   ).toThrowError(/Couldn't find export doesNotExist from .*custom-preset.js - got undefined/)
+})
 
+test('errors for export with wrong type', () => {
   expect(() =>
     preset.custom({
       meta: {filename: __filename, existingContent: ''},
       options: {source: './invalid-custom-preset.js', input: 'abc'},
     })
   ).toThrowError(/Couldn't find export function from .*invalid-custom-preset.js - got object/)
 })
+
+test('can require module first', () => {
+  expect(() =>
+    preset.custom({
+      meta: {filename: __filename, existingContent: ''},
+      options: {source: './custom-preset.js', require: 'thismoduledoesnotexist'},
+    })
+  ).toThrowError(/Cannot find module 'thismoduledoesnotexist' from 'src\/presets\/custom.ts'/)
+})

packages/eslint-plugin-codegen/src/presets/custom.ts

@@ -20,14 +20,34 @@ import type {Preset} from '.'
  *
  * `<!-- codegen:start {preset: custom, source: ./lib/my-custom-preset.js, export: jsonPrinter, myCustomProp: hello}`
  *
- * @param source Relative path to the module containing the custom preset
+ * @param source Relative path to the module containing the custom preset.
  * @param export The name of the export. If omitted, the module itself should be a preset function.
+ * @param require A module to load before `source`. If not set, defaults to `ts-node/register/transpile-only` for typescript sources.
+ * @param dev Set to `true` to clear the require cache for `source` before loading. Allows editing the function without requiring an IDE reload.
  */
-export const custom: Preset<{source: string; export?: string} & Record<string, any>> = ({meta, options}) => {
-  const sourcePath = path.join(path.dirname(meta.filename), options.source)
+export const custom: Preset<
+  {
+    source?: string
+    export?: string
+    require?: string
+    dev?: boolean
+  } & Record<string, unknown>
+> = ({meta, options}) => {
+  const sourcePath = options.source ? path.join(path.dirname(meta.filename), options.source) : meta.filename
   if (!fs.existsSync(sourcePath) || !fs.statSync(sourcePath).isFile()) {
-    throw Error(`Source path doesn't exist: ${sourcePath}`)
+    throw Error(`Source path is not a file: ${sourcePath}`)
   }
+
+  const requireFirst = options.require || (sourcePath.endsWith('.ts') ? 'ts-node/register/transpile-only' : undefined)
+  if (requireFirst) {
+    require(requireFirst)
+  }
+
+  if (options.dev) {
+    // eslint-disable-next-line @typescript-eslint/no-dynamic-delete
+    delete require.cache[sourcePath]
+  }
+
   // eslint-disable-next-line @typescript-eslint/no-var-requires
   const sourceModule = require(sourcePath)
   const func = options.export ? sourceModule[options.export] : sourceModule