@polkadot/types-codec

What is @polkadot/types-codec?

@polkadot/types-codec is a library that provides a set of utilities for encoding and decoding data types used in the Polkadot ecosystem. It is part of the larger Polkadot JS API suite and is essential for interacting with the Polkadot blockchain, particularly for handling the various custom data types defined in the Polkadot runtime.

What are @polkadot/types-codec's main functionalities?

Encoding and Decoding

This feature allows you to encode and decode data types. In this example, a u8 (unsigned 8-bit integer) is encoded to a byte array and then decoded back to its original value.

const { TypeRegistry, u8, u32 } = require('@polkadot/types-codec');

const registry = new TypeRegistry();
const encoded = new u8(registry, 123).toU8a();
const decoded = new u8(registry, encoded);
console.log(decoded.toNumber()); // 123

Type Creation

This feature allows you to create custom types. In this example, a custom struct type with fields 'age' and 'name' is created and instantiated.

const { TypeRegistry, Struct, u32, Text } = require('@polkadot/types-codec');

const registry = new TypeRegistry();
const MyStruct = Struct.with({
  age: u32,
  name: Text
});
const instance = new MyStruct(registry, { age: 30, name: 'Alice' });
console.log(instance.toJSON()); // { age: 30, name: 'Alice' }

Type Conversion

This feature allows you to convert types to different formats. In this example, a u32 (unsigned 32-bit integer) is converted to its hexadecimal and string representations.

const { TypeRegistry, u32 } = require('@polkadot/types-codec');

const registry = new TypeRegistry();
const value = new u32(registry, 12345);
console.log(value.toHex()); // '0x00003039'
console.log(value.toString()); // '12345'

Other packages similar to @polkadot/types-codec

protobufjs

protobufjs is a library for encoding and decoding Protocol Buffers (protobuf). It provides similar functionality for handling custom data types, but it is more general-purpose and not specific to the Polkadot ecosystem.

msgpack

msgpack is a library for encoding and decoding MessagePack, an efficient binary serialization format. Like @polkadot/types-codec, it focuses on efficient data encoding and decoding, but it is not tailored to blockchain-specific data types.

bson

bson is a library for encoding and decoding BSON (Binary JSON). It is used primarily in MongoDB but provides similar functionality for handling binary data encoding and decoding, though it is not specific to blockchain data types.

README

@polkadot/types-codec

Base scale-codec types.

Changelog

10.12.4 Mar 19, 2024

Contributed:

• Fix add muln(2) to signingInfo Derive (Thanks to https://github.com/pepoviola)