Got error if using hint from Dockerfile to pass arguments

[Boldie]

If one uses the hint from the Dockerfile to pass arguments, the script exits with an error:

$ docker run --rm 118f2b38c69f -e "unifi-password=supersekrit"
[eval]:1
unifi-password=supersekrit
^^^^^^^^^^^^^^

SyntaxError: Invalid left-hand side in assignment
    at new Script (vm.js:84:7)
    at createScript (vm.js:258:10)
    at Object.runInThisContext (vm.js:306:10)
    at Object.<anonymous> ([eval]-wrapper:9:26)
    at Module._compile (internal/modules/cjs/loader.js:1121:30)
    at evalScript (internal/process/execution.js:80:25)
    at internal/main/eval_string.js:23:3