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@medishn/toolkit Core Utilities Documentation

This document explains the fundamental building blocks used throughout the toolkit. These utilities help write cleaner, safer TypeScript code.

Basic Type Helpers

1. Constructor

What it does:
Represents a class blueprint. Useful when working with classes directly.

Example:

class Car {}
const createVehicle = (ctor: Constructor<Car>) => new ctor();
createVehicle(Car); // Works!

2. Maybe

What it does:
"Maybe there's a value, maybe not." Represents optional values.

Example:

let username: Maybe<string>; // Can be string, null, or undefined
username = 'John';
username = null; // Also OK

3. Dictionary

What it does:
A fancy name for simple key-value objects.

Example:

const prices: Dictionary<number> = {
  apple: 1.99,
  banana: 0.99,
};

4. Numeric

What it does:
For when you need to work with both regular numbers and big numbers.

Example:

function add(a: Numeric, b: Numeric): Numeric {
  return a + b; // Works with 5 or 9007199254740991n
}

Type Safety Helpers

5. Primitive & PrimitiveObject

What they do:

  • Primitive: Basic value types (string, number, etc.)
  • PrimitiveObject: Their object versions (String, Number, etc.)

Example:

function logValue(val: Primitive) {
  console.log(val); // Accepts "hello", 42, true, etc.
}

6. Noop & Callback

What they do:

  • Noop: Empty function placeholder
  • Callback: Flexible function with arguments

Example:

const emptyFunction: Noop = () => {};
const buttonClick: Callback<[MouseEvent]> = (event) => {...};

Advanced

7. Nullable

What it does:
Makes all properties in an object optional (can be null).

Example:

type User = { name: string; age: number };
type SafeUser = Nullable<User>; // { name: string|null; age: number|null }

8. NonX Types

What they do:

  • NonNull<T>: No nulls allowed
  • NonUndefined<T>: No undefined
  • NonNullable<T>: No null/undefined

Example:

function requireValue(val: NonNull<string>) {
  // val can't be null here
}

HTTP Status Codes

9. HttpStatus Enum

What it does:
Named constants for HTTP status codes. No more remembering numbers!

Common uses:

res.status(HttpStatus.NOT_FOUND); // Instead of 404
if (errorCode === HttpStatus.UNAUTHORIZED) { ... }

Full list includes:

HttpStatus.OK; // 200
HttpStatus.NOT_FOUND; // 404
HttpStatus.I_AM_A_TEAPOT; // 418 🫖
HttpStatus.INTERNAL_SERVER_ERROR; // 500

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