colon and semicolon are not allowed as keys about json

[NPrada]

I am having the same issue, I believe it has to do with having a '-' in one of the json keys,
if you try run your command without the '-' it will work without errors, eg:
json -I -f package.json -e 'this.scripts.cypresscucumberpreprocessor={}'

[trentm]

The argument to -e or -c is JS code. What you passed there is not legal JavaScript code, so this is by design.

You can do somethjing like this:

$ echo '{
    "name":"cypress-ci",
    "description":"cypress tests",
    "version":"1.0.0",
    "license": "UNLICENSED",
    "private": true,
    "scripts": {}
}' | json -e 'this.scripts["cypress-cucumber-preprocessor"] = {}'
{
  "name": "cypress-ci",
  "description": "cypress tests",
  "version": "1.0.0",
  "license": "UNLICENSED",
  "private": true,
  "scripts": {
    "cypress-cucumber-preprocessor": {}
  }
}