error1

 yarn preTest
yarn run v1.22.4
warning ../../../package.json: No license field
$ node -r esm src/testing-utils/preTest.js
internal/modules/cjs/loader.js:985
  throw err;
  ^

Error: Cannot find module 'esm'
Require stack:
- internal/preload
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:982:15)
    at Function.Module._load (internal/modules/cjs/loader.js:864:27)
    at Module.require (internal/modules/cjs/loader.js:1044:19)
    at Module._preloadModules (internal/modules/cjs/loader.js:1298:12)
    at loadPreloadModules (internal/bootstrap/pre_execution.js:444:5)
    at prepareMainThreadExecution (internal/bootstrap/pre_execution.js:68:3)
    at internal/main/run_main_module.js:7:1 {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ 'internal/preload' ]
}
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
solidity@gray ~/C/R/ens-app> npm install esm
npm notice created a lockfile as package-lock.json. You should commit this file.
+ [email protected]
added 1 package from 1 contributor and audited 1 package in 1.4s
found 0 vulnerabilities

error2

yarn run v1.22.4
warning ../../../package.json: No license field
$ node -r esm src/testing-utils/preTest.js
/home/solidity/Code/RTradeLtd/ens-app/src/testing-utils/preTest.js:1
Error: Cannot find module '@ensdomains/mock'
Require stack:
- /home/solidity/Code/RTradeLtd/ens-app/src/testing-utils/preTest.js
    at Object.<anonymous> (/home/solidity/Code/RTradeLtd/ens-app/src/testing-utils/preTest.js:1) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    '/home/solidity/Code/RTradeLtd/ens-app/src/testing-utils/preTest.js'
  ]
}
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.