checker.js

A set of boilerplate utilities for checking any type of values ​​without headaches or common mistakes

Installation

With pnpm

pnpm install @nawael/checker.js --save

With npm

npm install @nawael/checker.js --save

With yarn

yarn add @nawael/checker.js --save

Integration

For CommonJS

const { isArray, isString, isNumber, ... } = require('@nawael/checker.js')

For ESM

import { isArray, isString, isNumber, ... } from '@nawael/checker.js'

Usage examples

// instead of using typeof
if (typeof arg === 'object') {
  // ...some stuff
  // But if we do Object.keys(arg) we throw an error if arg is null! 😱
  // TypeError: Cannot convert undefined or null to object
}

// use isObject
import { isObject } from '@nawael/checker.js'

isObject(arg)
// ✅ true if arg = {}
// ❌ false if arg = null cause typeof null === 'object'
// ❌ false if arg = [] cause typeof [] === 'object'

// instead of using typeof
if (typeof arg === 'number') {
  // some stuff
}

// use isNumber
import { isNumber } from '@nawael/checker.js'

isNumber(arg)
// ✅ true if arg = 0 or arg = Infinity or -Infinity or
// ✅ true if arg = new Number() cause typeof new Number() === 'object'
// ❌ false if arg = NaN cause NaN is a number and we need to avoid NaN
// 😱 so we must check Object.prototype.toString.call(arg) === '[object Number]'

[!TIP] All APIs are available in the standalone "is" API

// instead of importing all API
import { isArray, isString, isNumber, ... } from '@nawael/checker.js'

// use "is" API and avoid boring imports
import { is } from '@nawael/checker.js'

is.array(arg) // isArray(arg)
is.string(arg) // isString(arg)
is.number(arg) // isNumber(arg)

// ...and so on

Available APIs

primitive checker

| APIs | standalone is | | -------------------- | --------------------- | | isBoolean(arg) | is.boolean(arg) | | isBooleanOrNull(arg) | is.booleanOrNull(arg) | | isBigInt(arg) | is.bigInt(arg) | | isNumber(arg) | is.number(arg) | | isNull(arg) | is.null(arg) | | isString(arg) | is.string(arg) | | isUndefined(arg) | is.undefined(arg) | | isSymbol(arg) | is.symbol(arg) | | isPrimitive(arg) | is.primitive(arg) |

String checker

| APIs | standalone is | | --------------------- | --------------------------- | | isStringOrNull(arg) | is.string.orNull(arg) | | isStringEmpty(arg) | is.string.empty(arg) | | isStringNotEmpty(arg) | is.string.notEmpty(arg) | | isAlpha(arg) | is.string.alpha(arg) | | isNumeric(arg) | is.string.numeric(arg) | | isAlphanumeric(arg) | is.string.alphanumeric(arg) | | isEmail(arg) | is.string.email(arg) | | isUrl(arg) | is.string.url(arg) | | isBinaryString(arg) | is.string.binary(arg) | | isBase64(arg) | is.string.base64(arg) |

Number checker

| APIs | standalone is | | ---------------------------------- | ------------------------------------------ | | isPositiveNumber(arg) | is.number.positive(arg) | | isNegativeNumber(arg) | is.number.negative(arg) | | isInfinite(arg) | is.number.infinite(arg) | | isOdd(arg) | is.number.odd(arg) | | isEven(arg) | is.number.even(arg) | | isNumberOrNull(arg) | is.number.orNull(arg) | | isDecimal(arg) | is.number.decimal(arg) | | isGreaterThan(arg, compare) | is.number.greaterThan(arg, compare) | | isGreaterEqualThan(arg, compare) | is.number.greaterEqualThan(arg, compare) | | isLessThan(arg, compare) | is.number.lessThan(arg, compare) | | isLessEqualThan(arg, compare) | is.number.lessEqualThan(arg, compare) | | isBetween(arg, start, finish) | is.number.between(arg, start, finish) | | isBetweenEqual(arg, start, finish) | is.number.betweenEqual(arg, start, finish) |

Object checker

| APIs | standalone is | | --------------------- | ----------------------- | | isObject(arg) | is.object(arg) | | isObjectOrNull(arg) | is.object.orNull(arg) | | isObjectNotEmpty(arg) | is.object.notEmpty(arg) | | isObjectEmpty(arg) | is.object.empty(arg) |

Array checker

| APIs | standalone is | | ---------------------- | ---------------------- | | isArray(arg) | is.array(arg) | | isMap(arg) | is.map(arg) | | isSet(arg) | is.set(arg) | | isArrayOrNull(arg) | is.array.orNull(arg) | | isArrayOfNumbers(arg) | is.array.number(arg) | | isArrayOfStrings(arg) | is.array.string(arg) | | isArrayOfObjects(arg) | is.array.object(arg) | | isArrayOfBooleans(arg) | is.array.boolean(arg) | | isArrayNotEmpty(arg) | is.array.notEmpty(arg) | | isArrayEmpty(arg) | is.array.empty(arg) |

Function checker

| APIs | standalone is | | ------------------------ | ----------------- | | isFunction(arg) | is.function(arg) | | isAsyncFunction(arg) | is.async(arg) | | isGeneratorFunction(arg) | is.generator(arg) |

Promise checker

| APIs | standalone is | | ------------------------ | -------------------------- | | isPromise(arg) | is.promise(arg) | | isFullfilledPromise(arg) | is.promise.fullfilled(arg) | | isRejectedPromise(arg) | is.promise.rejected(arg) | | isPendingPromise(arg) | is.promise.pending(arg) |

Misc checker

| APIs | standalone is | | ------------- | -------------- | | isDate(arg) | is.date(arg) | | isRegExp(arg) | is.regExp(arg) | | isError(arg) | is.error(arg) | | isFalsy(arg) | is.falsy(arg) | | isTruthy(arg) | is.truthy(arg) |

UUID checker

| APIs | standalone is | | ------------- | -------------- | | isUUID(arg) | is.uuid(arg) | | isUUIDv3(arg) | is.uuidv3(arg) | | isUUIDv4(arg) | is.uuidv4(arg) | | isUUIDv5(arg) | is.uuidv5(arg) |

Environment checker

| APIs | standalone is | | ------------- | -------------- | | isWindow() | is.window() | | isNode() | is.node() | | isBrowser() | is.browser() | | isJsDom() | is.jsDom() | | isWebWorker() | is.webWorker() | | isBun() | is.bun() | | isMac() | is.mac() | | isLinux() | is.linux() | | isWindows() | is.windows() |

Platform checker

| APIs | standalone is | | ----------------- | ------------------ | | isIpad() | is.ipad() | | isIphone() | is.iphone() | | isIpod() | is.ipod() | | isAndroid() | is.android() | | isAndroidPhone() | is.androidPhone() | | isAndroidTablet() | is.androidTablet() | | isMobile() | is.mobile() | | isTablet() | is.tablet() | | isDesktop() | is.desktop() | | isIos() | is.ios() |

Browser checker

| APIs | standalone is | | ------------- | -------------- | | isChrome() | is.chrome() | | isFirefox() | is.firefox() | | isOpera() | is.opera() | | isOperaMini() | is.operaMini() | | isSafari() | is.safari() | | isEdge() | is.edge() | | isIe() | is.ie() |

IP checker

| APIs | standalone is | | ----------- | ------------- | | isIPv4(arg) | is.ipv4(arg) | | isIPv6(arg) | is.ipv6(arg) | | isIP(arg) | is.ip(arg) |