Fix ESM/CJS compatibility

.eslintrc

@@ -20,8 +20,14 @@
     "node": true
   },
   "settings": {
-    "import/extensions": [".js", ".ts"]
+    "import/extensions": [".js", ".ts"],
+    "import/resolver": {
+      "typescript": {
+        "project": ["./tsconfig.json"]
+      }
+    }
   },
+  "ignorePatterns": ["/dist/**"],
   "rules": {
     "@typescript-eslint/no-unused-vars": [
       "error",

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [14.x, 16.x, 18.x]
+        node-version: [16.x, 18.x]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v2

package.json

@@ -5,9 +5,21 @@
   "license": "MIT",
   "repository": "git://github.com/MetaMask/superstruct.git",
   "type": "module",
+  "exports": {
+    ".": {
+      "import": {
+        "default": "./dist/index.mjs",
+        "types": "./dist/index.d.mts"
+      },
+      "require": {
+        "default": "./dist/index.cjs",
+        "types": "./dist/index.d.cts"
+      }
+    }
+  },
   "main": "./dist/index.cjs",
   "module": "./dist/index.mjs",
-  "types": "./dist/index.d.ts",
+  "types": "./dist/index.d.cts",
   "sideEffects": false,
   "files": [
     "dist"
@@ -16,39 +28,36 @@
     "registry": "https://registry.npmjs.org"
   },
   "engines": {
-    "node": ">=14.0.0"
+    "node": ">=16.0.0"
   },
   "devDependencies": {
-    "@babel/cli": "^7.6.3",
-    "@babel/core": "^7.6.3",
-    "@babel/plugin-transform-modules-commonjs": "^7.12.1",
-    "@babel/preset-env": "^7.20.2",
-    "@babel/preset-typescript": "^7.6.0",
-    "@babel/register": "^7.6.2",
     "@rollup/plugin-typescript": "^9.0.2",
     "@types/expect": "^24.3.0",
     "@types/lodash": "^4.14.144",
+    "@types/lodash-es": "^4.17.12",
     "@types/mocha": "^10.0.0",
     "@types/node": "^18.7.14",
     "@typescript-eslint/eslint-plugin": "^5.43.0",
     "@typescript-eslint/parser": "^5.43.0",
-    "babel-eslint": "^10.0.3",
     "eslint": "^7.14.0",
     "eslint-config-prettier": "^7.2.0",
-    "eslint-plugin-import": "^2.22.1",
+    "eslint-import-resolver-typescript": "^3.6.1",
+    "eslint-plugin-import": "^2.29.1",
     "eslint-plugin-prettier": "^4.0.0",
     "is-email": "^1.0.0",
     "is-url": "^1.2.4",
     "is-uuid": "^1.0.2",
-    "lodash": "^4.17.15",
+    "jest": "^29.7.0",
+    "lodash-es": "^4.17.21",
     "mocha": "^10.0.0",
     "np": "^7.6.2",
     "prettier": "^2.0.5",
     "rollup": "^3.3.0",
-    "typescript": "^4.8.3"
+    "typescript": "^4.8.3",
+    "vitest": "^1.2.2"
   },
   "scripts": {
-    "build": "rm -rf ./{dist} && rollup --config ./rollup.config.js",
+    "build": "rm -rf ./dist && rollup --config ./rollup.config.js && scripts/split-tsd-files.sh",
     "clean": "rm -rf ./{dist,node_modules}",
     "fix": "npm run fix:eslint && npm run fix:prettier",
     "fix:eslint": "npm run lint:eslint --fix",
@@ -57,8 +66,8 @@
     "lint:eslint": "eslint '{src,test}/*.{js,ts}'",
     "lint:prettier": "prettier --list-different '**/*.{js,json,ts}'",
     "release": "npm run build && npm run lint && np",
-    "test": "npm run build && npm run test:types && npm run test:mocha",
-    "test:mocha": "mocha --require ./test/register.cjs --require source-map-support/register ./test/index.ts",
+    "test": "npm run build && npm run test:types && npm run test:vitest",
+    "test:vitest": "vitest run",
     "test:types": "tsc --noEmit && tsc --project ./test/tsconfig.json --noEmit",
     "watch": "npm run build -- --watch"
   },

scripts/split-tsd-files.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+set -euo pipefail
+
+for file in dist/*.d.ts dist/structs/*.d.ts; do
+  mv $file "${file%.d.ts}.d.cts"
+  cp "${file%.d.ts}.d.cts" "${file%.d.ts}.d.mts"
+done
+
+for file in dist/*.d.cts dist/structs/*.d.cts; do
+  echo "File: $file"
+  sed -e 's/\.d\.ts/.d.cts/' -i.bak "$file"
+  sed -e 's/\.js/.cjs/' -i.bak "$file"
+done
+
+for file in dist/*.d.mts dist/structs/*.d.mts; do
+  echo "File: $file"
+  sed -e 's/\.d\.ts/\.d\.mts/' -i.bak "$file"
+  sed -e 's/\.js/.mjs/' -i.bak "$file"
+done
+
+find dist -name '*.bak' | xargs rm

src/index.ts

@@ -1,6 +1,6 @@
-export * from './error'
-export * from './struct'
-export * from './structs/coercions'
-export * from './structs/refinements'
-export * from './structs/types'
-export * from './structs/utilities'
+export * from './error.js'
+export * from './struct.js'
+export * from './structs/coercions.js'
+export * from './structs/refinements.js'
+export * from './structs/types.js'
+export * from './structs/utilities.js'

src/struct.ts

@@ -1,5 +1,5 @@
-import { toFailures, shiftIterator, StructSchema, run } from './utils'
-import { StructError, Failure } from './error'
+import { toFailures, shiftIterator, StructSchema, run } from './utils.js'
+import { StructError, Failure } from './error.js'
 
 /**
  * `Struct` objects encapsulate the validation logic for a specific type of

src/structs/coercions.ts

@@ -1,6 +1,6 @@
-import { Struct, is, Coercer } from '../struct'
-import { isPlainObject } from '../utils'
-import { string, unknown } from './types'
+import { Struct, is, Coercer } from '../struct.js'
+import { isPlainObject } from '../utils.js'
+import { string, unknown } from './types.js'
 
 /**
  * Augment a `Struct` to add an additional coercion step to its input.

src/structs/refinements.ts

@@ -1,5 +1,5 @@
-import { Struct, Refiner } from '../struct'
-import { toFailures } from '../utils'
+import { Struct, Refiner } from '../struct.js'
+import { toFailures } from '../utils.js'
 
 /**
  * Ensure that a string, array, map, or set is empty.

src/structs/types.ts

@@ -1,5 +1,5 @@
-import { Infer, Struct } from '../struct'
-import { define } from './utilities'
+import { Infer, Struct } from '../struct.js'
+import { define } from './utilities.js'
 import {
   ObjectSchema,
   ObjectType,
@@ -9,7 +9,7 @@ import {
   AnyStruct,
   InferStructTuple,
   UnionToIntersection,
-} from '../utils'
+} from '../utils.js'
 
 /**
  * Ensure that any value passes validation.

src/structs/utilities.ts

@@ -1,6 +1,11 @@
-import { Context, Struct, Validator } from '../struct'
-import { Assign, ObjectSchema, ObjectType, PartialObjectSchema } from '../utils'
-import { object, optional, type } from './types'
+import { Context, Struct, Validator } from '../struct.js'
+import {
+  Assign,
+  ObjectSchema,
+  ObjectType,
+  PartialObjectSchema,
+} from '../utils.js'
+import { object, optional, type } from './types.js'
 
 /**
  * Create a new struct that combines the properties properties from multiple

src/utils.ts

@@ -1,5 +1,5 @@
-import { Struct, Infer, Result, Context, Describe } from './struct'
-import { Failure } from './error'
+import { Struct, Infer, Result, Context, Describe } from './struct.js'
+import { Failure } from './error.js'
 
 /**
  * Check if a value is an iterator.

test/api/assert.ts → test/api/assert.test.ts

@@ -1,5 +1,6 @@
 import { throws, doesNotThrow } from 'assert'
 import { assert, string, StructError } from '../../src'
+import { describe, it } from 'vitest'
 
 describe('assert', () => {
   it('valid as helper', () => {

test/api/create.ts → test/api/create.test.ts

@@ -1,3 +1,4 @@
+import { describe, it } from 'vitest'
 import { strictEqual, deepEqual, deepStrictEqual, throws } from 'assert'
 import {
   type,

test/api/is.ts → test/api/is.test.ts

@@ -1,3 +1,4 @@
+import { describe, it } from 'vitest'
 import { strictEqual } from 'assert'
 import { is, string } from '../../src'
 

test/api/mask.ts → test/api/mask.test.ts

@@ -1,3 +1,4 @@
+import { describe, it } from 'vitest'
 import { deepStrictEqual, throws } from 'assert'
 import {
   mask,

test/api/validate.ts → test/api/validate.test.ts

@@ -1,3 +1,4 @@
+import { describe, it } from 'vitest'
 import { deepStrictEqual, strictEqual } from 'assert'
 import {
   validate,

test/index.ts → test/index.test.ts

@@ -1,6 +1,6 @@
 import assert, { CallTracker } from 'assert'
 import fs from 'fs'
-import { pick } from 'lodash'
+import { pick } from 'lodash-es'
 import { basename, extname, resolve } from 'path'
 import {
   any,
@@ -12,15 +12,9 @@ import {
   StructError,
 } from '../src'
 
-describe('superstruct', () => {
-  describe('api', () => {
-    require('./api/assert')
-    require('./api/create')
-    require('./api/is')
-    require('./api/mask')
-    require('./api/validate')
-  })
+import { describe, it } from 'vitest'
 
+describe('superstruct', () => {
   describe('validation', () => {
     const kindsDir = resolve(__dirname, 'validation')
     const kinds = fs
@@ -29,15 +23,15 @@ describe('superstruct', () => {
       .map((t) => basename(t, extname(t)))
 
     for (const kind of kinds) {
-      describe(kind, () => {
+      describe(kind, async () => {
         const testsDir = resolve(kindsDir, kind)
         const tests = fs
           .readdirSync(testsDir)
           .filter((t) => t[0] !== '.')
           .map((t) => basename(t, extname(t)))
 
         for (const name of tests) {
-          const module = require(resolve(testsDir, name))
+          const module = await import(resolve(testsDir, name))
           const { Struct, data, create, only, skip, output, failures } = module
           const run = only ? it.only : skip ? it.skip : it
           run(name, () => {

test/tsconfig.json

@@ -1,4 +1,8 @@
 {
   "extends": "../tsconfig.json",
-  "include": ["./**/*.ts"]
+  "include": ["./**/*.ts"],
+  "compilerOptions": {
+    "lib": ["esnext"],
+    "skipLibCheck": true
+  }
 }

test/typings/any.ts

@@ -1,5 +1,5 @@
 import { assert, any } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<any>((x) => {
   assert(x, any())

test/typings/array.ts

@@ -1,5 +1,5 @@
 import { assert, array, number } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<Array<unknown>>((x) => {
   assert(x, array())

test/typings/assign.ts

@@ -1,5 +1,5 @@
 import { assert, assign, object, number, string } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<{
   a: number

test/typings/bigint.ts

@@ -1,5 +1,5 @@
 import { assert, bigint } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<bigint>((x) => {
   assert(x, bigint())

test/typings/boolean.ts

@@ -1,5 +1,5 @@
 import { assert, boolean } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<boolean>((x) => {
   assert(x, boolean())

test/typings/coerce.ts

@@ -1,5 +1,5 @@
 import { assert, coerce, string, number } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<number>((x) => {
   assert(

test/typings/date.ts

@@ -1,5 +1,5 @@
 import { assert, date } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<Date>((x) => {
   assert(x, date())

test/typings/defaulted.ts

@@ -1,5 +1,5 @@
 import { assert, defaulted, string } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<string>((x) => {
   assert(x, defaulted(string(), 'Untitled'))

test/typings/deprecated.ts

@@ -1,5 +1,5 @@
 import { assert, object, deprecated, any, Context } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<unknown>((x) => {
   const log = (value: unknown, ctx: Context) => {}

test/typings/describe.ts

@@ -28,7 +28,7 @@ import {
   min,
   pattern,
 } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<Describe<any>>((x) => {
   return any()

test/typings/dynamic.ts

@@ -1,5 +1,5 @@
 import { assert, dynamic, string } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<string>((x) => {
   assert(

test/typings/empty.ts

@@ -1,5 +1,5 @@
 import { assert, empty, string, array, map, set } from '../../src'
-import { test } from '..'
+import { test } from '../index.test'
 
 test<string>((x) => {
   assert(x, empty(string()))