Monkey Patch for the unfriendly errors thrown by Sequelize 6

monkeyPatchSequelizeErrorsForJest.js

/**
 * This monkey patch fixes an error reporting issue with sequelize errors in tests,
 * which was fixed in Sequelize v7, but hasn't been back-ported to Sequelize v6.
 * See https://github.com/sequelize/sequelize/issues/14807#issuecomment-1854398131
 *
 * It should only be used in the test env, to make Sequelize error messages show up.
 * This can be removed when we upgrade to Sequelize 7, or when the issue is fixed in v6.
 */

const { Sequelize } = require('sequelize')

const sequelizeVersion = Sequelize['version'] || '6.x.x' // doesn't (currently) exist in v6
const major = Number(sequelizeVersion.split('.')[0])

if (major >= 7) {
  console.warn(
    'This patch was probably made redundant in Sequelize v7, you should check!'
  )
}

/**
 * @param {Sequelize} instance An instance of Sequelize
 * @returns {Sequelize} Monkey-patched Sequelize instance that throws Jest-compatible errors
 */
function monkeyPatchSequelizeErrorsForJest(instance) {
  if (typeof jest === 'undefined') return instance

  const origQueryFunc = instance.query
  instance.query = async function query(...args) {
    let result
    try {
      result = await origQueryFunc.apply(this, args)
    } catch (err) {
      throw fixSequelizeError(err)
    }
    return result
  }

  return instance
}

const isSequelizeError = e =>
  e instanceof Error && e.name.startsWith('Sequelize')

const fixSequelizeError = error => {
  if (!isSequelizeError(error)) return error

  let { message } = error.parent
  if (error.sql) {
    message += '\nSQL: ' + error.sql
  }

  if (error.parameters) {
    const stringifiedParameters = JSON.stringify(error.parameters)
    if (
      stringifiedParameters !== 'undefined' &&
      stringifiedParameters !== '{}'
    ) {
      message += '\nParameters: ' + stringifiedParameters
    }
  }

  message += '\n' + error.stack

  error.message = message
  Error.captureStackTrace(error)

  return error
}

module.exports = monkeyPatchSequelizeErrorsForJest

Thanks for writing this! Really makes me happy!