[REQ][typescript-inversify] Change 'optional' behavior

[siada]

Is your feature request related to a problem? Please describe.

When generating models for a .net API, I have to add the [Required] attribute to every model property to avoid the typescript-inversify generator creating view model properties as optional.

The problem with them being optional is typescripts 'undefined by default' approach - you end up with a lot of undefined checks against properties that are never going to be undefined.

The problem this causes is the model validator on the .net side is validating properties as [Required] that are actually allowed to be null - but they're defined as [Required] so typescript-inversify doesn't try to make them undefined

Describe the solution you'd like

Change the default behaviour of declaring a typescript-inversify model property from:

name?: string

to a union type:

name: string | null

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[amakhrov]

Isn't nullable what you are looking for?

However, in general I don't see a practical difference between undefined and null. Could you please clarify why do you want to handle them differently in your typescript code?

TSLint even has a rule that bans using null in a codebase (and provides some good reasons for that)

[siada]

You might be right that nullable is what I'm after, but that's not supported in the typescript-inversify generator:

https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/resources/typescript-inversify/modelGeneric.mustache#L8

An example of the benefit's I can see to this change(whether it be nullable or changing the behavior of required) is on a view model, I've defined something such as:

name: string;
jobTitle: string;

It's perfectly acceptable for these fields to be null, however they will never be undefined. The problem I have is that I map from an api model, to this view model for rendering, and the api model generates as:

name?: string;
jobTitle?: string;

Which then forces me to do:

const response: PersonViewModel = {
    name: apiResponse.name || null,
    jobTitle: apiResponse.jobTitle || null
};

Otherwise the linter throws a bitch fit because string | undefined cannot be assigned to string.

The ? from the type disappears if I mark the fields as [Required] in my api, but this then breaks the contract because the api will reject if the properties are null, but I actually expect them on certain conditions to be null, they're only [Required] so that typescript-inversify doesn't generate them as | undefined

[amakhrov]

Ok, so what I hear is that typescript-inversify generator lacks support for nullable (unlike some other typescript generators).
Would you want to file a PR fixing that?

[siada]

I'll submit the PR and see if that fixes my issue

[siada]

PR Submitted #5568

[macjohnny]

fixed with #5568