Adds help messages to the help command

[andreban]

Closes #87

[PEConn]

You can use template literals for multiline strings.

[PEConn]

(if you want, I'm also fine with this way.)

[andreban]

Tried it out, but it kind of breaks the indentation, as otherwise the blank characters at the beginning of the line are printed.

[PEConn]

Oh yeah, I'd have it formatted something like:

const HELP_MESSAGES = new Map<string, string> (
    [
      ['main',
`
llama-pack [command] <options>

build ............... generates an Android APK from a TWA Project
help ................ shows this menu
`],
      ['init',
`
...
`

But yeah, I'm fine with your way. (Mixing the indent of code and output strings is usually horrible - I guess the "proper" way to do this would be to have the help strings nicely formatted in text files that we read in (and it would allow for easier internationalisation, if we ever get that far!).

[PEConn]

Yeah, so what you want here is an ! (a (Non-null assertion operator)[https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-0.html#non-null-assertion-operator]).

[andreban]

Interestingly, the linter configuration dislikes it:

 69:12  warning  Forbidden non-null assertion  @typescript-eslint/no-non-null-assertion

[andreban]

Here's the rule: https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-non-null-assertion.md

I can keep the current role and the rule or add an eslint-ignore-line. I kind of prefer the first.

[PEConn]

I disagree with that rule - the point of strict null checking is for the compiler to catch things for you that you would have missed. In this case, we've acknowledged the possibility of null and said that we want to crash if that's the case.

Sorry, I don't understand what you're saying with "I can keep the current role and the rule"

[andreban]

I agree. Changed eslint.json to remove the rule and removed the unnecessary check from help.ts.