Idealy pick a common license for code

[jaller94]

public domain in package.json is not a common SPDX license code, which makes it hard to contribute, use this package and perform automatic license checks.

mixmap/package.json

Line 29 in c633916

"license": "public domain"

Ideally all past contributors agree on a license from this list:
https://spdx.org/licenses/

These are popular options explained: https://choosealicense.com/

I recommend going with MIT, but if you wish to remove the need for attribution (as public domain does), MIT-0 may be the less common alternative.