@silen/is-undefined v1.0.3

is-undefined

Determine if a value is Undefined

install

npm i @silen/is-undefined

api

• declare function isUndefined(val: any): boolean;

usage

const { isUndefined } = require('@silen/is-undefined');
// or
import { isUndefined } from '@silen/is-undefined';

console.log(isUndefined(new Buffer(4)));
console.log(isUndefined(Buffer.alloc(4)));
console.log(isUndefined(undefined));
console.log(isUndefined(null));
console.log(isUndefined(''));
console.log(isUndefined(true));
console.log(isUndefined(0));
console.log(isUndefined(1));
console.log(isUndefined(1.0));
console.log(isUndefined('string'));
console.log(isUndefined({}));
console.log(isUndefined(function foo() {}));
console.log(isUndefined(Symbol()));
console.log(isUndefined(new Set));
console.log(isUndefined(new Map));
console.log(isUndefined(new WeakMap));
console.log(isUndefined(new WeakSet));

// or
console.log(window.Type.isUndefined(new WeakSet));

This is a demo for testing the usage of isUndefined from @silen/is-undefined module. You can try the others and do likewise.

others

• type
• isArray
• isNull
• isBoolean
• isBuffer
• isArrayBuffer
• isFormData
• isArrayBufferView
• isString
• isNumber
• isObject
• isPlainObject
• isDate
• isArguments
• isFile
• isBlob
• isFunction
• isSymbol
• isRegExp
• isInt8Array
• isUint8Array
• isUint8ClampedArray
• isInt16Array
• isUint16Array
• isInt32Array
• isUint32Array
• isFloat32Array
• isFloat64Array
• isError
• isPromise
• isSet
• isWeakSet
• isMap
• isWeakMap
• isStream
• isURLSearchParams