x-is-type

x-is-type is a minimal package for simple type-checks of basic types.

Package is bundled using microbundle

Installation

npm i x-is-type

In Node.js

// ESM:
import { isNum, isStr, isObj } from 'x-is-type';
// CommonJS:
const { isNum, isStr, isObj } = require('x-is-type');

Usage

This package includes the following functions for type checking of one or more variables.

/** Check if typeof value is 'number' and not NaN */
isNum(1);
// => true
isNum(NaN);
// => false

/**
 * Check if typeof value is 'number',
 * not NaN and integers
 */
isInt(1);
// => true
isInt(1.1);
// => false

/**
 * Check if typeof value is 'number',
 * not NaN and floating point numbers
 */
isFloat(1.1);
// => true
isFloat(1);
// => false

/** Check if typeof value is 'string' */
isStr('1');
// => true
isStr(1);
// => false

/** Check if typeof value is 'boolean' */
isBool(false);
// => true
isBool(null);
// => false

/**
 * Check if typeof value is 'object',
 * not null and instances of ObjectConstructor
 */
isObj({ foo: 'bar' });
// => true
isObj(null);
// => false

/** Check if value is an array, (uses Array.isArray) */
isArr([1, 2, 3]);
// => true
isArr({});
// => false

/** Check if typeof value is 'function' */
isFn(() => {});
// => true
isFn({});
// => false

/** Check if value is null */
isNull(null);
// => true
isNull(undefined);
// => false

/** Check if value is undefined */
isUndef(undefined);
// => true
isUndef(null);
// => false

/** Check if value is an instance of DateConstructor */
isDate(new Date());
// => true
isDate(Date.now());
// => false

/**
 * Check if value is an instance of DateConstructor
 * and contains valid dates
 */
isValidDate(new Date(1970, 1, 1));
// => true
isValidDate(new Date('hello'));
// => false

/** Check if typeof value is 'symbol' */
isSymbol(Symbol(123));
// => true
isSymbol(123);
// => false

/** Check if value is an instance of MapConstructor */
isMap(new Map());
// => true
isMap({ foo: 'bar' });
// => false

/** Check if value is an instance of SetConstructor */
isSet(new Set());
// => true
isSet(new Array());
// => false

/** Check if x is any non-falsy value */
isTruthy(1);
// => true
isTruthy(0);
// => false

/** Check if x is any falsy value */
isFalsy(0);
// => true
isFalsy(1);
// => false