@zerodep/is-integer

A simple, performant utility to determine if a value is a finite integer.

Full documentation is available at the zerodep.app page.

Signature

declare const isInteger: (value: unknown) => boolean;

Examples

All @zerodep packages support both ESM and CJS formats, each complete with Typescript typings.

// ESM
import { isInteger } from '@zerodep/is-integer';

// CJS
const { isInteger } = require('@zerodep/is-integer');

// Arrays
isInteger([]); // false
isInteger([1, 2, 3]); // false
isInteger(['a', 'b', 'c']); // false

// BigInts
isInteger(42n); // false
isInteger(0n); // false
isInteger(-0n); // false
isInteger(-42n); // false

// Booleans
isInteger(true); // false
isInteger(false); // false

// Class
isInteger(
  class SomeClass {
    constructor() {}
  }
); // false

// Dates
isInteger(new Date()); // false
isInteger(new Date('1970-01-01T12:00:00.000Z')); // false
isInteger(new Date('2099-12-31')); // false

// Empty
isInteger(null); // false
isInteger(undefined); // false

// Errors
isInteger(new Error('message')); // false
isInteger(new AggregateError([new Error('err1'), new Error('err2')], 'message')); // false

// Floats
isInteger(3.14); // false
isInteger(0.0); // true  <-- CAUTION: zero is allowed as an integer
isInteger(-0.0); // true  <-- CAUTION: zero is allowed as an integer
isInteger(-3.14); // false
isInteger(Math.E); // false
isInteger(Math.PI); // false
isInteger(Number.MIN_VALUE); // false

// Functions
isInteger(() => 'function'); // false
isInteger(async () => 'function'); // false

// Generators
isInteger(function* () {
  yield 'a';
}); // false
isInteger(async function* () {
  yield 'a';
}); // false

// Maps
isInteger(new Map()); // false
isInteger(new Map([['key1', 123]])); // false
isInteger(new Map([['key1', 'value1']])); // false

// Numbers
isInteger(Number.POSITIVE_INFINITY); // false
isInteger(Number.MAX_SAFE_INTEGER); // true
isInteger(3e8); // true
isInteger(42); // true
isInteger(1); // true
isInteger(0); // true
isInteger(-0); // true
isInteger(-1); // true
isInteger(-42); // true
isInteger(-3e8); // true
isInteger(Number.MIN_SAFE_INTEGER); // true
isInteger(Number.NEGATIVE_INFINITY); // false
isInteger(Number.NaN); // false

// POJOs
isInteger({}); // false
isInteger({ key: 'string' }); // false
isInteger({ key: 123 }); // false

// Promise
isInteger(new Promise(() => {})); // false
isInteger(new Promise.all([])); // false
isInteger(new Promise.allSettled([])); // false
isInteger(new Promise.race([])); // false
isInteger(Promise.resolve()); // false

// Regular Expression
isInteger(/[regex]+/gi); // false
isInteger(new RegExp('d', 'gi')); // false

// Sets
isInteger(new Set()); // false
isInteger(new Set([1, 2, 3])); // false
isInteger(new Set(['a', 'b', 'c'])); // false

// Strings
isInteger(''); // false
isInteger('a longer string'); // false
isInteger('1000n'); // false
isInteger('3e8'); // false
isInteger('42'); // false
isInteger('3.14'); // false
isInteger('0'); // false
isInteger('-0'); // false
isInteger('-3.14'); // false
isInteger('-42'); // false
isInteger('-3e8'); // false
isInteger('-1000n'); // false

// Symbols
isInteger(Symbol()); // false
isInteger(Symbol('name')); // false

// This
isInteger(this); // false
isInteger(globalThis); // false

// TypedArrays
isInteger(new Int8Array(2)); // false
isInteger(new Int16Array(2)); // false
isInteger(new Int32Array(2)); // false
isInteger(new Uint8Array(2)); // false
isInteger(new Uint16Array(2)); // false
isInteger(new Uint32Array(2)); // false
isInteger(new Uint8ClampedArray(2)); // false

isInteger(new BigInt64Array(2)); // false
isInteger(new BigUint64Array(2)); // false

isInteger(new Float32Array(2)); // false
isInteger(new Float64Array(2)); // false

isInteger(new SharedArrayBuffer(512)); // false

// WeakMap and WeakSet
isInteger(new WeakMap()); // false
isInteger(new WeakSet()); // false

ZeroDep Advantages

• Zero npm dependencies - completely eliminates all risk of supply-chain attacks, decreases node_modules folder size
• ESM & CJS - has both ecmascript modules and common javascript exports
• Tree Shakable - built to be fully tree shakable ensuring your packages are the smallest possible size
• Fully typed - typescript definitions are provided for every package for a better developer experience
• Semantically named - package and method names are easy to grok, remember, use, and read
• Documented - actually useful documentation with examples at zerodep.app
• Intelligently Packaged - multiple npm packages of different sizes available allowing a menu or a-la-carte composition of capabilities
• 100% Tested - all methods and packages are fully unit tested
• Predictably Versioned - semantically versioned for peace-of-mind upgrading, this includes changelogs
• MIT Licensed - permissively licensed for maximum usability