The 'TypePKI' library is an opensource free TypeScript PKI library which is the successor of the long lived jsrsasign library.
The 'typepki-asn1parse' is a ASN.1 parser utility for TypePKI library.
import { asn1parse } from "typepki-asn1parse";
console.log(asn1parse("300602010a02010b"));
This shows
{
  "t": "seq",
  "v": [
    { "t": "int", "v": "0a" },
    { "t": "int", "v": "0b" },
  ]
}
Result will be a Record object which has following members:
| short name | ASN.1 name | code | value | value sample | 
|---|---|---|---|---|
| bool | INTEGER | 01 | ||
| int | INTEGER | 02 | ||
| bitstr | BitString | 03 | ||
| octstr | OctetString | 04 | ||
| null | NULL | 05 | ||
| oid | ObjectIdentifier | 06 | {oid: "0.2.3.15"} | |
| enum | Enumerated | 0a | ||
| utf8str | UTF8String | 0c | {str: "りんご3"} | |
| prnstr | PrintableString | 13 | {str: "test12"} | |
| ia5str | IA5String | 16 | {str: "u1@example.com"} | |
| utctime | UTCTime | 17 | 131231235959Z | |
| gentime | GeneralizedTime | 18 | 20131231235959Z | |
| seq | SEQUENCE | 30 | array of Record | [{t:"int",v:"0123"}] | 
| set | SET | 31 | array of Record | [{t:"int",v:"0123"}] | 
When the ASN.1 value is a ASN.1 TLV or a sequence of ASN.1 TLV, the V will also be parsed.
This will be applied to ASN.1 application tag TLV such as "[0]" or "[1]".