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

A workaround for sequelize/sequelize#14807

This should cause errors to have the correct stack trace and error name, such that Jest will print out the error that occurred.
To use this, just import it wherever you define your Sequelize DB, and do something like:

    const monkeyPatchSequelizeErrorsForJest = require('./monkeyPatchSequelizeErrorsForJest')

    if (process.env.NODE_ENV === "test") {
      return monkeyPatchSequelizeErrorsForJest(sequelize)
    } else {
      return sequelize
    }

(It will always reference the monkeyPatch file as the source of the error, but you can look down the stack trace to find the real source)

Updated so that the error thrown is actually the original error class, not a new invented one (since validating the class of the error thrown may be important for some tests)