"Object is possibly 'undefined'." during npm install

[fvirdia]

On a freshly cloned repo, running npm install results in the error below.
Adding "strictNullChecks": false, to tsconfig.json seems to solve the issue.

> remarkable-typescript@1.0.7 prepare /media/fernando/shared/reMarkable-typescript
> npx tsc

node_modules/getmac/source/index.ts:26:23 - error TS2532: Object is possibly 'undefined'.

26              for (const part of parts) {
                                   ~~~~~
Found 1 error.