@bitgo/unspents

The package provides a Dimensions class with methods to calculate bitcoin transaction sizes

Installation

npm install --save @bitgo/unspents

Dimensions, Virtual Size Estimation

The transaction vSize is critical to calculating the proper transaction fee.

The class unspents.Dimensions provides a class that helps work with the components required to calculate an accurate estimate of a transaction vSize.

Examples

import { Codes, Dimensions } from '@bitgo/unspents';
// using raw attributes
new Dimensions({
  nP2shInputs: 1,
  nP2shP2wshInputs: 1,
  nP2wshInputs: 1,
  outputs: { count: 1, size: 32 },
});

// calculate from unspents that have `chain` property (see Chain Codes)
Dimensions.fromUnspents(unspent[0]);
Dimensions.fromUnspents(unspents);

// Signed inputs work too
Dimensions.fromInput(inputs[0]);
Dimensions.fromInputs(inputs);

// Transaction outputs
Dimensions.fromOutputs(outputs[0]);
Dimensions.fromOutputs(outputs);
Dimensions.fromOutputOnChain(Codes.p2sh.internal);
Dimensions.fromOutputScriptLength(31);

// Combining dimensions and estimating their vSize
Dimensions.fromUnspents({ unspents })
  .plus(Dimensions.fromOutputOnChain(Codes.p2shP2wsh.internal).times(nOutputs))
  .getVSize();

Continuous Integration

@bitgo/unspents uses github actions for continuous integration, which is configured by the .github/workflows/ci.yml file in the project root. All changes to the CI process should be done by modifying the .github/workflows/ci.yml file.

Codes

The exported Codes module is now deprecated.

Please use utxo-lib/src/bitgo/wallet/chains instead.