add Required, Purify, NonNullable, closes #15 (#16)

Author: gcanti

CHANGELOG.md

@@ -1,43 +1,49 @@
 # Changelog
 
 > **Tags:**
-> - [New Feature]
-> - [Bug Fix]
-> - [Breaking Change]
-> - [Documentation]
-> - [Internal]
-> - [Polish]
-> - [Experimental]
+>
+> * [New Feature]
+> * [Bug Fix]
+> * [Breaking Change]
+> * [Documentation]
+> * [Internal]
+> * [Polish]
+> * [Experimental]
 
-**Note**: Gaps between patch versions are faulty/broken releases.
-**Note**: A feature tagged as Experimental is in a high state of flux, you're at risk of it changing without notice.
+**Note**: Gaps between patch versions are faulty/broken releases. **Note**: A feature tagged as Experimental is in a
+high state of flux, you're at risk of it changing without notice.
+
+# 0.2.2
+
+* **New Feature**
+  * add `Required`, `Purify`, `NonNullable`, closes #15 (@gcanti)
 
 # 0.2.1
 
-- **New Feature**
-  - add `ObjectOptional`, closes #13 (@thepheer)
+* **New Feature**
+  * add `ObjectOptional`, closes #13 (@thepheer)
 
 # 0.2.0
 
-- **Breaking Change**
-  - complete refactoring
-  - upgrade to TypeScript 2.5.2 (@gcanti)
+* **Breaking Change**
+  * complete refactoring
+  * upgrade to TypeScript 2.5.2 (@gcanti)
 
 # 0.1.3
 
-- **New Feature**
-  - `NumberToNat`
-  - `NatToNumber`
-  - hlists
-  - tuples
-  - convert tuples to / from hlists (`TupleToTHList`, `THListToTuple`)
+* **New Feature**
+  * `NumberToNat`
+  * `NatToNumber`
+  * hlists
+  * tuples
+  * convert tuples to / from hlists (`TupleToTHList`, `THListToTuple`)
 
 # 0.1.2
 
-- **Bug Fix**
-  - remove `ObjectExact` (@gcanti)
+* **Bug Fix**
+  * remove `ObjectExact` (@gcanti)
 
 # 0.1.1
 
-- **New Feature**
-  - `PickExact` (@gcanti)
+* **New Feature**
+  * `PickExact` (@gcanti)

README.md

@@ -1,19 +1,19 @@
 # Compatibility
 
-- `0.2.0+` for TypeScript `2.5.2+`
-- `0.1.3` for TypeScript `2.4.1+`
+* `0.2.0+` for TypeScript `2.5.2+`
+* `0.1.3` for TypeScript `2.4.1+`
 
 # Credits
 
 Adapted from
 
-- https://github.com/Microsoft/TypeScript/issues/14833
-- https://github.com/Microsoft/TypeScript/issues/16392
-- https://github.com/Microsoft/TypeScript/issues/12215
+* https://github.com/Microsoft/TypeScript/issues/14833
+* https://github.com/Microsoft/TypeScript/issues/16392
+* https://github.com/Microsoft/TypeScript/issues/12215
 
 ## Related projects
 
-- [typical - playground for type-level primitives in TypeScript](https://github.com/tycho01/typical) by @tycho01
+* [typical - playground for type-level primitives in TypeScript](https://github.com/tycho01/typical) by @tycho01
 
 # Examples
 
@@ -95,4 +95,3 @@ class Foo extends React.Component<{ bar: string; baz: number }> {}
 const FilledFoo = withProps(Foo, { baz: 1 })
 const x = <FilledFoo bar="bar" /> // ok
 ```
-

package.json

@@ -1,14 +1,16 @@
 {
   "name": "typelevel-ts",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "description": "Type level programming in TypeScript",
   "files": ["lib"],
   "main": "lib/index.js",
   "typings": "lib/index.d.ts",
   "scripts": {
     "lint": "tslint src/**/*.ts",
-    "typings-checker": "typings-checker --allow-expect-error --project typings-checker/tsconfig.json typings-checker/index.ts",
-    "prettier": "prettier --no-semi --single-quote --print-width 120 --parser typescript --list-different \"{src,typings-checker}/**/*.ts\"",
+    "typings-checker":
+      "typings-checker --allow-expect-error --project typings-checker/tsconfig.json typings-checker/index.ts",
+    "prettier":
+      "prettier --no-semi --single-quote --print-width 120 --parser typescript --list-different \"{src,typings-checker}/**/*.ts\"",
     "test": "npm run prettier && npm run lint && npm run typings-checker",
     "clean": "rm -rf lib/*",
     "build": "npm run clean && tsc"
@@ -25,10 +27,10 @@
   "homepage": "https://github.com/gcanti/typelevel-ts",
   "dependencies": {},
   "devDependencies": {
-    "prettier": "1.5.2",
+    "prettier": "1.8.2",
     "tslint": "4.4.2",
     "tslint-config-standard": "4.0.0",
-    "typescript": "2.6.0-rc",
+    "typescript": "2.6.1",
     "typings-checker": "1.1.2"
   },
   "tags": [],

src/index.ts

@@ -176,6 +176,12 @@ export type ObjectOptional<O, K extends keyof O> = ObjectOmit<O, K> & Partial<Pi
 
 export type PickExact<O, K extends keyof O> = Pick<O, K> & { [K1 in StringOmit<keyof O, K>]?: never }
 
+export type Required<T> = { [P in Purify<keyof T>]: NonNullable<T[P]> }
+
+export type Purify<T extends string> = { [P in T]: T }[T]
+
+export type NonNullable<T> = T & {}
+
 //
 // hlists
 //

typings-checker/index.ts

@@ -139,3 +139,20 @@ const natToString0: t.NatToString<t.Zero> = '0'
 const natToString1: t.NatToString<t.One> = '1'
 const natToString2: t.NatToString<t.Two> = '2'
 const natToString10: t.NatToString<t.Ten> = '10'
+
+//
+// Required
+//
+type R1 = {
+  a: string
+  b?: number
+  c?: boolean | null | undefined
+}
+type RR1 = t.Required<R1>
+// $ExpectError Property 'a' is missing in type '{}'
+const r1: RR1 = {}
+// $ExpectError Property 'b' is missing in type '{ a: string; }'
+const r2: RR1 = { a: 'a' }
+// $ExpectError Property 'c' is missing in type '{ a: string; b: number; }'
+const r3: RR1 = { a: 'a', b: 1 }
+const r4: RR1 = { a: 'a', b: 1, c: true }

typings-checker/tsconfig.json

@@ -10,7 +10,5 @@
     "strictNullChecks": true,
     "target": "es5"
   },
-  "lib": [
-    "es6", "dom"
-  ]
+  "lib": ["es6", "dom"]
 }