isJWT

The isJWT function checks if a string matches the format of a valid JSON Web Token (JWT).

Syntax

isJWT(value)

Parameters

Parameter	Type	Description
value	string	Token to be checked.

Return

Type	Description
boolean	Returns true if the string matches the format of a valid JWT, otherwise returns false.

Examples

isJWT('eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c'); // true
isJWT('abc.def.ghi'); // true
isJWT('abc.def');     // false
isJWT('abc');         // false

Notes

• Throws a TypeError if the provided value is not a string.
• Does not validate the signature or content of the token, only the format.

References

• RFC 7519: JSON Web Token (JWT)
• MDN: String.prototype.test()