Mapped Types

Mapped Types Utilities for TypeScript Projects

• Thoroughly tested for type correctness
• No third-party dependencies
• Semantic Versioning
• Output separate bundles for different workflow needs (es5-commonjs, es5-module, jsnext)

Table of Contents

Mapped Types

• DiffKeys
• OmitKeys
• Diff
• Omit
• Overwrite
• Assign

Type Utils

• getReturnOfExpression

Redux Typesafe Actions

DEPRECATION WARNING: this part will be removed in next major release, please use typesafe-actions directly instead!

Reimported from typesafe-actions

API Docs

• createAction
• getType
• isActionOf

Archived docs:

• Docs v2.X

Mapped Types

DiffKeys

DiffKeys<K extends string, L extends string>
Compare set of keys K and L and return a subset with a difference

Usage:

import { OmitKeys } from 'react-redux-typescript';

interface BaseProps { a: string, b?: number, c: boolean }
interface Props { a: number, d: number }

type Diffed_Keys = DiffKeys<keyof Props, keyof Props2>;
// Expect: 'b' | 'c'

OmitKeys

OmitKeys<K extends string, K2 extends K>
From set of keys K subtract it's subset K2

Usage:

import { OmitKeys } from 'react-redux-typescript';

interface BaseProps { a: string, b?: number, c: boolean }

type Omitted_Keys = OmitKeys<keyof BaseProps, 'a'>;
// Expect: 'b' | 'c'

Diff

Diff<T extends object, U extends object>
From T remove intersecting properties with U

Usage:

import { OmitKeys } from 'react-redux-typescript';

interface BaseProps { a: string, b?: number, c: boolean }
interface Props { a: number, d: number }

type Diffed_Props = Diff<BaseProps, Props>;
// Expect { b?: number | undefined, c: boolean }

Omit

Omit<T extends object, K extends keyof T>
From T remove a set of properties K

Usage:

import { OmitKeys } from 'react-redux-typescript';

interface BaseProps { a: string, b?: number, c: boolean }

type Omitted_Props = Omit<BaseProps, 'a'>;
// Expect: { b?: number | undefined, c: boolean }

Overwrite

Overwrite<T extends object, U extends object>
Replace intersecting properties from U to T

Usage:

import { OmitKeys } from 'react-redux-typescript';

interface BaseProps { a: string, b?: number, c: boolean }
interface Props { a: number, d: number }

type Overwritten_Props = Overwrite<BaseProps, Props>;
// Expect: { a: number, b?: number | undefined, c: boolean }

Assign

Assign<T extends object, U extends object>
Copy and replace all properties from U to T

Usage:

import { Assign } from 'react-redux-typescript';

interface BaseProps { a: string, b?: number, c: boolean }
interface Props { a: number, d: number }

type Assigned_Props = Assign<BaseProps, Props>;
// Expect: { a: number, b?: number | undefined, c: boolean, d: number }

Type Utils

getReturnOfExpression

Get return value of an "expression" with inferred return type
Alias: returntypeof https://github.com/Microsoft/TypeScript/issues/6606

// this polyfill exist because TypeScript does not support getting type of expression 
// (tracking issue: https://github.com/Microsoft/TypeScript/issues/6606)
function getReturnOfExpression<T>(
  expression: (...params: any[]) => T,
): T;

// Example:
import { getReturnOfExpression } from 'react-redux-typescript';

const increment = () => ({ type: 'INCREMENT' as 'INCREMENT' });

const returnOfIncrement = getReturnOfExpression(increment);
type INCREMENT = typeof returnOfIncrement; // { type: "INCREMENT"; }

MIT License

Copyright (c) 2016 Piotr Witek [email protected] (http://piotrwitek.github.io)