@everget/typeof v3.0.1

typeOf

A smart replacement of the typeof operator and robust type checker. This is my first ever published module on npm (2017). I have rewritten it to the modern stack (TypeScript, Vitest) without functional changes.

Installation

pnpm add @everget/typeof

Usage

const typeOf = require('@everget/typeof');
// or
import typeOf from '@everget/typeof';

let value = 'awesome string';

typeOf(value)();
// => 'string'

typeOf(value) == 'string';
// => true

typeOf(value).expect('string');
// => true

typeOf(value).expect('number');
// => TypeError: The value is of type `string`, but expected `number`

/** NOTE: you must use `==` operator for correct work */
let isMap = (value) => typeOf(value)() == 'map';

let smth = new Map();

if (isMap(smth)) {
  /** Do your staff */
}

let isFunction = (value) => {
  return typeOf(value).expect('function|asyncfunction|generatorfunction');
}

let smth = async () => {};

if (isFunction(smth)) {
  /** Do your staff */
}

function sum(a, b) {
  typeOf(a).expect('number');
  typeOf(b).expect('number');

  return typeOf(a + b).expect('number') && (a + b);
}

sum(1, () => {});
// => TypeError: The value is of type `function`, but expected `number`

sum(1, 2);
// => 3

Examples of returned values

ES

ES6, ES7

Browser

Node.js

Tests

npm test

Release History

• 0.1.0 Initial release
• 0.1.1 Added detection of typed arrays
• 2.0.0 Corrections for global object, Math, JSON, async functions and generators
• 3.0.0 Implemented new usage syntax. Added correct detection of iterators