Mint Assets

Create a Minting Policy

First, we need to create a minting policy for the assets we want to mint. In this example, we'll use a native script time-locking policy with our wallet as the required signer:

const address = await lucid.wallet().address();
 
const mintingPolicy = scriptFromNative({
  type: "all",
  scripts: [
    { type: "sig", keyHash: paymentCredentialOf(address).hash },
    {
      type: "before",
      slot: unixTimeToSlot(lucid.config().network, Date.now() + 1000000),
    },
  ],
});

Next we derive the policy id from the minting policy script:

const policyId = mintingPolicyToId(mintingPolicy);

Mint Assets

Now we can mint our desired tokens:

const tx = await lucid
  .newTx()
  .mintAssets({
    [policyId + fromText("MyToken")]: 1n,
    [policyId + fromText("MyOtherToken")]: 1n,
  })
  .pay.ToAddress(address, { [policyId + fromText("MyToken")]: 1n })
  .validTo(Date.now() + 900000)
  .attach.MintingPolicy(mintingPolicy)
  .complete();
 
const signed = await tx.sign.withWallet().complete();
const txHash = await signed.submit();
ℹ️

When working with script parameters (involving nested structures or custom data types):

const scriptWithParams = applyParamsToScript(
  yourCompiledScript,
  [param1, param2, ...]
);
  • Minting tokens creates them, but it doesn't automatically assign them to any address. After minting, the tokens are technically "owned" by the transaction itself.
  • Purpose of pay.ToAddress() is to send the newly minted tokens to a specific address

CIP68 Token Standard

CIP68 is a token standard that extends CIP25 to provide richer metadata functionality.

Define the CIP68 datum schema

const CIP68DatumSchema = Data.Object({
metadata: Data.Map(Data.Any(), Data.Any()),
version: Data.Integer(),
});
type CIP68DatumSchemaType = Data.Static<typeof CIP68DatumSchema>;
const CIP68Datum = CIP68DatumSchema as unknown as CIP68DatumSchemaType;
 
const metadataMap = new Map();
metadataMap.set(fromText("myKey"), Data.to(fromText("myValue")));
 
const metadataCBOR = Data.to(
{ metadata: metadataMap, version: 0n },
CIP68Datum
);
 
const tx = await lucid
.newTx()
.mintAssets({
[policyId + fromText("MyToken")]: 1n,
})
.pay.ToAddressWithData(
address,
{ kind: "inline", value: metadataCBOR },
{ [policyId + fromText("MyToken")]: 1n }
)
.validTo(Date.now() + 900000)
.attach.MintingPolicy(mintingPolicy)
.complete();
💡

An alternative way to define the metadata is to use an object:

const metadataObject = {
  [fromText("myKey")]: Data.to(fromText("myValue"))
}
 
const metadataCBOR = Data.to(
  { metadata: new Map(Object.entries(metadataObject)), version: 0n },
  CIP68Datum
);

Burn

To burn tokens, we use a similar process to minting, but with negative values for the assets we want to burn:

const tx = await lucid
  .newTx()
  .mintAssets({
    [policyId + fromText("MyToken")]: -1n,
    [policyId + fromText("MyOtherToken")]: -1n,
  })
  .validTo(Date.now() + 900000)
  .attach.MintingPolicy(mintingPolicy)
  .complete();
 
const signed = await tx.sign.withWallet().complete();
const txHash = await signed.submit();
💡
  • All assets minted in a single mintAssets call should be of the same policy id. You can chain multiple mintAssets calls if you need to mint assets with different policy ids
  • The minting policy must be attached to the transaction using attach.MintingPolicy
  • Lucid Evolution supports Native, PlutusV1 / V2 / V3 minting policies. The appropriate script type will be used based on the policy you attach.
  • When using Plutus scripts (V1 / V2 / V3), make sure to provide an appropriate redeemer.
  • The validTo field is important for time-locked minting policies to ensure the transaction is submitted within the valid time range
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