? options.defaults[mode] ?? options.defaults["all"]

[shouer-kong]

I encountered the following problem while trying to run the code. How can I solve it?

/opt/gpt/gpt4-with-calc/lib/engine/options.js:208
                            ? options.defaults[mode] ?? options.defaults["all"]
                                                      ^

SyntaxError: Unexpected token ?
    at new Script (vm.js:79:7)
    at createScript (vm.js:251:10)
    at Object.runInThisContext (vm.js:303:10)
    at Module._compile (internal/modules/cjs/loader.js:656:28)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:699:10)
    at Module.load (internal/modules/cjs/loader.js:598:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:537:12)
    at Function.Module._load (internal/modules/cjs/loader.js:529:3)
    at Module.require (internal/modules/cjs/loader.js:636:17)
    at require (internal/modules/cjs/helpers.js:20:18)

My operating environment： ubuntu 20.04 npm 6.4.1 nodejs 10.13.0