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@ckb-ccc/udt provides a TypeScript SDK for interacting with User Defined Tokens (UDT) and the xUDT standard on CKB. It is built on top of the SSRI protocol, supporting both SSRI-compliant contracts and legacy sUDT/xUDT tokens.
Installation
If you are using @ckb-ccc/shell, the udt namespace is already available as ccc.udt.
Exports
| Export | Description |
|---|
Udt | Main class for interacting with a UDT |
UdtPausable | Extended class for pausable UDT tokens |
The Udt class
Udt extends ssri.Trait and provides high-level methods for all token operations.
Constructor
const udt = new Udt(
code, // ccc.OutPointLike — the script code cell OutPoint
script, // ccc.ScriptLike — the type script identifying this token
config?, // { executor?: ssri.Executor | null }
);
Read methods
// Token metadata
const { res: name } = await udt.name(); // string | undefined
const { res: symbol } = await udt.symbol(); // string | undefined
const { res: decimals } = await udt.decimals(); // ccc.Num | undefined
const { res: icon } = await udt.icon(); // string (data URI) | undefined
transfer
Transfer tokens to one or more recipients:
async transfer(
signer: ccc.Signer,
transfers: { to: ccc.ScriptLike; amount: ccc.NumLike }[],
tx?: ccc.TransactionLike | null,
): Promise<ssri.ExecutorResponse<ccc.Transaction>>
mint
Mint new tokens (issuer only):
async mint(
signer: ccc.Signer,
mints: { to: ccc.ScriptLike; amount: ccc.NumLike }[],
tx?: ccc.TransactionLike | null,
): Promise<ssri.ExecutorResponse<ccc.Transaction>>
completeBy
Balance UDT inputs/outputs automatically using the signer’s address as change:
async completeBy(
tx: ccc.TransactionLike,
from: ccc.Signer,
): Promise<ccc.Transaction>
completeChangeToLock
Balance UDT inputs/outputs with a custom change lock script:
async completeChangeToLock(
txLike: ccc.TransactionLike,
signer: ccc.Signer,
change: ccc.ScriptLike,
): Promise<ccc.Transaction>
Usage examples
Transfer tokens
import { udt } from "@ckb-ccc/udt";
import { ccc } from "@ckb-ccc/shell";
const myToken = new udt.Udt(
{
txHash: "0x4e2e832e0b1e7b5994681b621b00c1e65f577ee4b440ef95fa07db9bb3d50269",
index: 0,
},
{
codeHash: "0xcc9dc33ef234e14bc788c43a4848556a5fb16401a04662fc55db9bb201987037",
hashType: "type",
args: "0x71fd1985b2971a9903e4d8ed0d59e6710166985217ca0681437883837b86162f",
},
);
const { script: toScript } = await ccc.Address.fromString(
"ckb1qzda0cr08m85hc8jlnfp3gog...",
signer.client,
);
// Build the transfer transaction
const { res: tx } = await myToken.transfer(signer, [
{ to: toScript, amount: 100n },
]);
// Balance UDT change and capacity
const completedTx = await myToken.completeBy(tx, signer);
await completedTx.completeInputsByCapacity(signer);
await completedTx.completeFeeBy(signer);
const txHash = await signer.sendTransaction(completedTx);
const { res: name } = await myToken.name();
const { res: symbol } = await myToken.symbol();
const { res: decimals } = await myToken.decimals();
console.log(`${name} (${symbol}), ${decimals} decimal places`);
Mint tokens
const { res: tx } = await myToken.mint(signer, [
{ to: recipientScript, amount: 1_000_000n },
]);
const completedTx = await myToken.completeBy(tx, signer);
await completedTx.completeInputsByCapacity(signer);
await completedTx.completeFeeBy(signer);
await signer.sendTransaction(completedTx);
@ckb-ccc/udt depends on @ckb-ccc/ssri. An ssri.Executor is optional —
without one, the Udt class falls back to constructing transactions directly
without querying SSRI metadata from the chain.