Simplify setup

.gitignore

@@ -1,8 +1 @@
-lib
-dist
-**/*.js
-**/*.flow
-!src/**/*.js
-!src/**/*.flow
-!test/**/*.js
-!test/**/*.flow
+/node_modules/

.npmrc

@@ -0,0 +1 @@
+package-lock=false

.travis.yml

@@ -1,7 +1,9 @@
 language: node_js
-sudo: false
 node_js:
-- 'stable'
+ - '8.10.0'
+ - '8'
+ - '10'
+ - '12'
 deploy:
  provider: npm
  email: [email protected]

index.d.ts

@@ -0,0 +1,2 @@
+declare function unreachable (value: never): never
+export = unreachable

index.js

@@ -0,0 +1,5 @@
+// @flow
+
+module.exports = function unreachable (value /*: empty */) /*: empty */ {
+ throw new TypeError('Internal error: Encountered impossible value: ' + JSON.stringify(value))
+}

index.test-d.ts

@@ -0,0 +1,24 @@
+import { expectError, expectType } from 'tsd'
+import unreachable = require('.')
+
+expectType<(value: never) => never>(unreachable)
+
+type Shape =
+ | { kind: 'square', size: number }
+ | { kind: 'rectangle', width: number, height: number }
+ | { kind: 'circle', radius: number }
+
+const area = (shape: Shape): number => {
+ switch (shape.kind) {
+ case 'square':
+ return shape.size * shape.size
+ case 'rectangle':
+ return shape.height * shape.width
+ case 'circle':
+ return Math.PI * shape.radius ** 2
+ default:
+ return unreachable(shape)
+ }
+}
+
+expectError(area({ kind: 'circl', radius: 7 }))

package.json

@@ -1,6 +1,6 @@
 {
- "version": "0.2.0",
  "name": "unreachable",
+ "version": "0.2.0",
  "description": "Utility function for exhaustiveness checking with typed JS (TS or Flow)",
  "keywords": [
  "unreachable",
@@ -16,39 +16,18 @@
  "switch",
  "default"
  ],
- "main": "lib/unreachable",
- "module": "src/unreachable",
- "types": "src/unreachable",
- "author": "Irakli Gozalishvili <[email protected]> (http:https://jeditoolkit.com)",
- "repository": "https://github.com/Gozala/unreachable",
+ "repository": "Gozala/unreachable",
  "license": "MIT",
- "devDependencies": {
- "babel-cli": "6.24.1",
- "babel-preset-flow-node": "^1.0.2",
- "babel-register": "6.24.1",
- "blue-tape": "^1.0.0",
- "documentation": "^5.1.0",
- "flow-bin": "^0.52.0",
- "flow-copy-source": "^1.2.0",
- "husky": "^0.14.0",
- "lint-staged": "^4.0.2",
- "prettier": "^1.5.3"
- },
+ "author": "Irakli Gozalishvili <[email protected]> (http:https://jeditoolkit.com)",
  "scripts": {
- "test": "npm run test:flow && npm run test:tape",
- "test:tape": "blue-tape -r babel-register test/**/*.js",
- "test:flow": "flow check",
- "build:clear": "rm -rf lib",
- "build:types": "flow-copy-source --verbose src lib",
- "build:node": "babel --out-dir lib src",
- "build:api": "documentation readme --section=API src/unreachable.js",
- "build:docs": "documentation build --document-exported src/** -f html --o docs",
- "build": "npm run build:node && npm run build:types",
- "prepublish": "npm run build && npm test",
- "precommit": "lint-staged",
- "start": "flow-copy-source --watch --verbose src lib & babel --watch --out-dir lib src"
+ "prepublish": "npm test",
+ "test": "standard && node test && tsd"
+ },
+ "devDependencies": {
+ "standard": "^14.3.3",
+ "tsd": "^0.11.0"
  },
- "lint-staged": {
- "*.js": ["prettier --parser flow --no-semi --write", "git add"]
+ "engines": {
+ "node": ">=8.10"
  }
 }

test.js

@@ -0,0 +1,9 @@
+const assert = require('assert')
+const unreachable = require('.')
+
+assert.strictEqual(typeof unreachable, 'function', 'default export is a function')
+
+assert.throws(
+ () => { unreachable({ kind: 'circl', radius: 7 }) },
+ new TypeError('Internal error: Encountered impossible value: {"kind":"circl","radius":7}')
+)