pb.types

Installation

npm install pb.types

Requirements

• typescript@>=5.0.0
• tsconfig.json > "compilerOptions" > { "strict": true }

API

• More information available as jsdoc strings in linked source files below.

Expect,Equal,NotEqual

• Expect
• Equal
• NotEqual

import type { Expect, Equal, NotEqual } from "pb.types";

const result = JSON.stringify({});

!0 as Expect<Equal<typeof result, string>>;
!0 as Expect<NotEqual<typeof result, number>>;

Disposer

• Disposer

import type { Disposer } from "pb.types";

function subscribe(): Disposer {
  // Start listener/subscription.
  return () => {
    // Stop listener/subscription.
  };
}

const disposer = subscribe();
//   ^ () => void

Modify

• Modify

import type { Modify } from "pb.types";

type Props = {
  label: string; // (required)
  onClick?: () => void; // (optional)
};

function Component(
  props: Modify<Props, { required: "onClick"; optional: "label" }>,
) {
  props.label;
  //    ^ string | undefined (optional)
  props.onClick;
  //    ^ () => void (required)
}

ArrayItem

• ArrayItem

import type { ArrayItem } from "pb.types";

type Item = ArrayItem<Array<string>>;
//   ^ string

Mutable

• Mutable

import type { Mutable } from "pb.types";

type MutableArray = Mutable<ReadonlyArray<number>>;
//   ^ Array<number>
type MutableSet = Mutable<ReadonlySet<number>>;
//   ^ Set<number>
type MutableMap = Mutable<ReadonlyMap<string, number>>;
//   ^ Map<string, number>
type MutableObject = Mutable<Readonly<{ foo: string; bar: number }>>;
//   ^ { foo: string; bar: number; }

Intersect

• Intersect

import type { Intersect } from "pb.types";

type Example = { A: true } | { B: true } | { C: true };
type Result = Intersect<Example>;
//   ^ { A: true } & { B: true } & { C: true }
//   ^ { A: true; B: true; C: true }

Identity

• Identity

import type { Identity } from "pb.types";

const value = Object.assign({ A: true }, { B: true });
//    ^ { A: boolean } & { B: boolean }
type _Result = Identity<typeof value>;
//   ^ { A: boolean; B: boolean }

branch

• branch

import { branch } from "pb.types";

void function example(): string | number | undefined {
  if (branch()) {
    return "abc";
  }

  if (branch()) {
    return 12345;
  }

  return undefined;
};