fundamentool

---

is

Variables

isArray

const isArray: (arg) => arg is any[] = Array.isArray;

Defined in: src/is/isArray.ts:11

Checks whether value is an Array.

Parameters

Parameter	Type
arg	any

Returns

arg is any[]

true if value is an Array.

Example

isArray([1, 2, 3]); // => true
isArray('hello');   // => false

---

isBlob

const isBlob: (instance) => boolean;

Defined in: src/is/isBlob.ts:12

Checks whether value is a Blob (when Blob is available).

Parameters

Parameter	Type
instance	any

Returns

boolean

true if value is a Blob instance.

Example

isBlob(new Blob(['data'])); // => true
isBlob('data');             // => false

---

isBuffer

const isBuffer: (instance) => boolean;

Defined in: src/is/isBuffer.ts:12

Checks whether value is a Buffer (in Node.js environments).

Parameters

Parameter	Type
instance	any

Returns

boolean

true if value is a Buffer instance.

Example

isBuffer(Buffer.from('data')); // => true
isBuffer('data');              // => false

---

isFormData

const isFormData: (instance) => boolean;

Defined in: src/is/isFormData.ts:12

Checks whether value is a FormData instance.

Parameters

Parameter	Type
instance	any

Returns

boolean

true if value is a FormData instance.

Example

isFormData(new FormData()); // => true
isFormData({});             // => false

---

isNaN

const isNaN: (v) => boolean = Number.isNaN;

Defined in: src/is/isNaN.ts:12

Checks whether value is NaN (wraps Number.isNaN). Unlike the global isNaN, does not coerce the value before checking.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true only if value is exactly NaN.

Example

isNaN(NaN);       // => true
isNaN(undefined); // => false (unlike global isNaN)
isNaN(1);         // => false

---

REGEXP_ASCII

const REGEXP_ASCII: RegExp;

Defined in: src/is/isASCII.ts:1

Functions

isArrayBuffer()

function isArrayBuffer(v): v is ArrayBuffer;

Defined in: src/is/isArrayBuffer.ts:10

Checks whether value is an ArrayBuffer.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is ArrayBuffer

true if value is an ArrayBuffer.

Example

isArrayBuffer(new ArrayBuffer(8)); // => true
isArrayBuffer([]);                 // => false

---

isArrayLike()

function isArrayLike(v): boolean;

Defined in: src/is/isArrayLike.ts:13

Checks whether value is array-like (non-null object with a valid numeric length).

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true if value is a non-null object with a valid length property.

Example

isArrayLike([1, 2]);        // => true
isArrayLike({ length: 3 }); // => true
isArrayLike('hello');       // => false

---

isASCII()

function isASCII(v): boolean;

Defined in: src/is/isASCII.ts:13

Checks whether a string contains only ASCII-printable characters.

Parameters

Parameter	Type	Description
v	string	The value to check.

Returns

boolean

true if the string is non-empty and contains only ASCII characters.

Example

isASCII('hello');  // => true
isASCII('привет'); // => false
isASCII('');       // => false

---

isBoolean()

function isBoolean(v): v is boolean;

Defined in: src/is/isBoolean.ts:11

Checks whether value is a boolean.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is boolean

true if value is a boolean.

Example

isBoolean(true);  // => true
isBoolean(false); // => true
isBoolean(1);     // => false

---

isCollection()

function isCollection(v): boolean;

Defined in: src/is/isCollection.ts:15

Checks whether value is a "collection": plain object or array-like object.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true if value is a non-null object with valid length or a plain object.

Example

isCollection([1, 2]);        // => true
isCollection({ a: 1 });      // => true
isCollection({ length: 3 }); // => true
isCollection('hello');       // => false

---

isDate()

function isDate(v): v is Date;

Defined in: src/is/isDate.ts:11

Checks whether value is a Date instance.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is Date

true if value is a Date.

Example

isDate(new Date());    // => true
isDate('2024-01-01'); // => false

---

isDefined()

function isDefined(v): boolean;

Defined in: src/is/isDefined.ts:12

Checks whether value is neither undefined nor null.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true if value is defined and not null.

Example

isDefined(0);         // => true
isDefined('');        // => true
isDefined(null);      // => false
isDefined(undefined); // => false

---

isDocumentStateReady()

function isDocumentStateReady(window): boolean;

Defined in: src/is/isDocumentStateReady.ts:12

Returns true when document.readyState is in interactive or complete state. In IE uses strict 'complete' check; in other browsers allows 'interactive'.

Parameters

Parameter	Type	Description
window	any	The window object to check against.

Returns

boolean

true if the document is ready.

Example

isDocumentStateReady(window); // => true (when DOM is ready)

---

isEmail()

function isEmail(v): boolean;

Defined in: src/is/isEmail.ts:11

Validates an email address using a project-specific regexp.

Parameters

Parameter	Type	Description
v	string	The value to validate.

Returns

boolean

true if value is a valid email address under 255 characters.

Example

isEmail('user@example.com'); // => true
isEmail('not-an-email');     // => false
isEmail('');                 // => false

---

isEmpty()

function isEmpty(src, k?): boolean;

Defined in: src/is/isEmpty.ts:10

Checks whether an object has no enumerable properties.

Parameters

Parameter	Type	Description
src	Record<string, any>	The object to check.
k?	string	-

Returns

boolean

true if the object has no enumerable properties.

Example

isEmpty({});        // => true
isEmpty({ a: 1 });  // => false

---

isEqual()

function isEqual(
   src1, 
   src2, 
   depth?): boolean;

Defined in: src/is/isEqual.ts:15

Deep equality check up to depth levels of nesting. At depth 0 (default), nested objects are compared by reference only.

Parameters

Parameter	Type	Description
src1	any	First value.
src2	any	Second value.
depth?	number	Nesting depth limit (default: 0).

Returns

boolean

true if both values are deeply equal within the given depth.

Example

isEqual(1, 1);                    // => true
isEqual({ a: 1 }, { a: 1 });      // => true
isEqual({ a: {} }, { a: {} });    // => false (depth 0, nested ref differs)
isEqual({ a: {} }, { a: {} }, 1); // => true  (depth 1, recurses into keys)

---

isFunction()

function isFunction(v): v is (args: any[]) => any;

Defined in: src/is/isFunction.ts:10

Checks whether value is a function.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is (args: any[]) => any

true if value is a function.

Example

isFunction(() => {}); // => true
isFunction({});       // => false

---

isHash()

function isHash(v, length?): boolean;

Defined in: src/is/isHash.ts:16

Checks whether value is a hex string of the given length (default 32).

Parameters

Parameter	Type	Default value	Description
v	any	undefined	The value to check.
length	number	32	Expected length of the hex string (default: 32).

Returns

boolean

true if value is a lowercase hex string of the expected length.

Example

isHash('a'.repeat(32));  // => true
isHash('abc123', 6);     // => true
isHash('xyz', 3);        // => false (non-hex chars)

---

isHttpUrl()

function isHttpUrl(url): boolean;

Defined in: src/is/isHttpUrl.ts:15

Validates an HTTP/HTTPS URL (supports both Latin and Cyrillic domains).

Parameters

Parameter	Type	Description
url	any	The value to validate.

Returns

boolean

true if value is a string matching a valid HTTP/HTTPS URL pattern.

Example

isHttpUrl('https://example.com'); // => true
isHttpUrl('not-a-url');           // => false

---

isIE()

function isIE(window): boolean;

Defined in: src/is/isIE.ts:11

Detects Internet Explorer by window.navigator.userAgent.

Parameters

Parameter	Type	Description
window	any	The window object to inspect.

Returns

boolean

true if the browser is Internet Explorer.

Example

isIE(window); // => false (in modern browsers)

---

isIndex()

function isIndex(v): boolean;

Defined in: src/is/isIndex.ts:14

Checks whether a string is a non-negative integer index.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true if value contains only digits (a valid array index string).

Example

isIndex('0');   // => true
isIndex('42');  // => true
isIndex('-1');  // => false
isIndex('1.5'); // => false

---

isInsign()

function isInsign(m): boolean;

Defined in: src/is/isInsign.ts:20

Checks that value is "insignificant":

• null/undefined (but NOT 0)
• empty array
• empty plain object

Parameters

Parameter	Type	Description
m	any	The value to check.

Returns

boolean

true if value is insignificant.

Example

isInsign(null);  // => true
isInsign([]);    // => true
isInsign({});    // => true
isInsign(0);     // => false
isInsign([1]);   // => false

---

isInteger()

function isInteger(v): boolean;

Defined in: src/is/isInteger.ts:12

Checks whether value is a 32-bit signed integer.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true if value is a 32-bit integer.

Example

isInteger(42);      // => true
isInteger(-1);      // => true
isInteger(1.5);     // => false
isInteger(2 ** 31); // => false (overflow)

---

isInvalidStringLength()

function isInvalidStringLength(v, length): boolean;

Defined in: src/is/isInvalidStringLength.ts:14

Returns true when value is not a string or has length less than required.

Parameters

Parameter	Type	Description
v	any	The value to check.
length	number	Minimum required length.

Returns

boolean

true if value is invalid (not a string or too short).

Example

isInvalidStringLength('hello', 3); // => false
isInvalidStringLength('hi', 3);    // => true
isInvalidStringLength(null, 3);    // => true

---

isLength()

function isLength(v): boolean;

Defined in: src/is/isLength.ts:19

Checks whether value is a valid array-like length.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true if value is a non-negative integer not exceeding Number.MAX_SAFE_INTEGER.

Example

isLength(0);   // => true
isLength(100); // => true
isLength(-1);  // => false
isLength(1.5); // => false

---

isMatch()

function isMatch(
   src, 
   matchs, 
   depth?): boolean;

Defined in: src/is/isMatch.ts:14

Checks whether src matches the structure of matchs up to depth levels (default: 10). Unlike isEqual, only the keys present in matchs are compared.

Parameters

Parameter	Type	Description
src	any	The value to test.
matchs	any	The pattern to match against.
depth?	number	Maximum recursion depth (default: 10).

Returns

boolean

true if all keys in matchs are present in src with equal values.

Example

isMatch({ a: 1, b: 2 }, { a: 1 }); // => true
isMatch({ a: 1 }, { a: 2 });        // => false
isMatch({ a: 1 }, { b: 1 });        // => false

---

isNumber()

function isNumber(v): v is number;

Defined in: src/is/isNumber.ts:11

Checks whether value is a number.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is number

true if value has type 'number' (including NaN).

Example

isNumber(42);  // => true
isNumber(NaN); // => true (NaN has type 'number')
isNumber('1'); // => false

---

isObject()

function isObject(v): v is object;

Defined in: src/is/isObject.ts:11

Checks whether value is a non-null object.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is object

true if value is an object and not null.

Example

isObject({});   // => true
isObject([]);   // => true
isObject(null); // => false

---

isObjectLike()

function isObjectLike(v): boolean;

Defined in: src/is/isObjectLike.ts:14

Checks whether value is object-like (object or function).

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

boolean

true if typeof v is 'object' or 'function' and value is truthy.

Example

isObjectLike({});       // => true
isObjectLike(() => {}); // => true
isObjectLike(null);     // => false
isObjectLike('str');    // => false

---

isPhone()

function isPhone(v): boolean;

Defined in: src/is/isPhone.ts:12

Validates a Russian phone number in the format +7(XXX)XXX-XX-XX.

Parameters

Parameter	Type	Description
v	string	The value to validate.

Returns

boolean

true if value matches the expected phone format.

Example

isPhone('+7(999)123-45-67'); // => true
isPhone('89991234567');      // => false

---

isPlainObject()

function isPlainObject(value): value is Record<string, any>;

Defined in: src/is/isPlainObject.ts:15

Checks whether value is a "plain object": an object whose prototype chain has at most Object.prototype or null.

Parameters

Parameter	Type	Description
value	any	The value to check.

Returns

value is Record<string, any>

true if value is a plain object.

Example

isPlainObject({});                  // => true
isPlainObject(Object.create(null)); // => true
isPlainObject([]);                  // => false
isPlainObject(new Date());          // => false

---

isPlainObjectBase()

function isPlainObjectBase(value): value is Record<string, any>;

Defined in: src/is/isPlainObject.ts:19

Parameters

Parameter	Type
value	any

Returns

value is Record<string, any>

---

isPromise()

function isPromise(v): v is Promise<any>;

Defined in: src/is/isPromise.ts:13

Checks whether value is a Promise (or thenable).

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is Promise<any>

true if value has a .then method.

Example

isPromise(Promise.resolve());   // => true
isPromise({ then: () => {} });  // => true
isPromise({});                  // => false

---

isRegExp()

function isRegExp(v): v is RegExp;

Defined in: src/is/isRegExp.ts:10

Checks whether value is a RegExp.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is RegExp

true if value is a RegExp instance.

Example

isRegExp(/abc/); // => true
isRegExp('abc'); // => false

---

isSafeNumber()

function isSafeNumber(v): boolean;

Defined in: src/is/isSafeNumber.ts:14

Checks that value can be parsed to a safe non-negative number less than 2147483647.

Parameters

Parameter	Type	Description
v	any	The value to check (coerced via parseFloat).

Returns

boolean

true if value parses to a valid non-negative safe number.

Example

isSafeNumber(100);        // => true
isSafeNumber('3.14');     // => true
isSafeNumber(-1);         // => false
isSafeNumber(2147483647); // => false (not less than MAX_SAFE_NUMBER)

---

isStandardObject()

function isStandardObject(value): boolean;

Defined in: src/is/isStandardObject.ts:14

Checks whether value is a "standard" object: plain object or array.

Parameters

Parameter	Type	Description
value	unknown	The value to check.

Returns

boolean

true if value is a plain object or an array.

Example

isStandardObject({});       // => true
isStandardObject([]);       // => true
isStandardObject(new Date()); // => false

---

isString()

function isString(v): v is string;

Defined in: src/is/isString.ts:10

Checks whether value is a string.

Parameters

Parameter	Type	Description
v	any	The value to check.

Returns

v is string

true if value has type 'string'.

Example

isString('hello'); // => true
isString(42);      // => false

---

isVisibleInViewport()

function isVisibleInViewport(element?): boolean;

Defined in: src/is/isVisibleInViewport.ts:9

Checks whether a DOM element is fully visible within the current viewport.

Parameters

Parameter	Type	Description
element?	HTMLElement	The element to check.

Returns

boolean

true if the element's bounding rect is fully inside the viewport.

Example

isVisibleInViewport(document.getElementById('btn')); // => true or false