efx-api-node/src/api/sign/cancel_order.js

<img src="https://avatars3.githubusercontent.com/u/33315316?s=200&v=4" align="right" />

const utils = require('ethereumjs-util')

module.exports = (efx, orderId) => {
  //orderId = utils.sha3(orderId.toString(16))

  //const toSign = utils.bufferToHex(orderId).slice(2)

  return efx.sign(orderId.toString(16))
}