Fix: Parameter with assignation provide type annotations (fixes #146)

[weirdpattern]

Adds code to process the type annotations on parameters that have assignations

[eslintbot]

LGTM

[JamesHenry]

Thanks so much for your efforts, @weirdpattern! I've been so swamped in January but things are set to improve from next week.

I will try my best to get to this at the weekend, but it will be by Monday at the latest.

[weirdpattern]

Perfect, could you please also take a look at issue #146, just want your input on that before I submit the PR

[soda0289]

@weirdpattern I think there are some more cases that need to include type annotations

//Missing
function iii(...name: string): string {
        return name;
}

//Handled correctly
function jjj(name: string): string {
        return name;
}

//Fixed by this PR
function kkk(name: string = 'hello'): string {
        return name;
}

//Missing
function lll(...name: string = 'hh'): string {
        return name;
}

Maybe we can avoid the duplicate code by setting a variable to the argument and then setting typeAnnotation on that.

[weirdpattern]

Hey @soda0289

//Missing
function iii(...name: Array<string>): Array<string> {
       return name;
}

I will look into this later today (I believe this was already being handled by the current code, but I can double check).

//Missing
function iii(...name: Array<string> = ['hi']): Array<string> {
       return name;
}

I don't think this even compiles, rest operators cannot have initializers here

Are you seeing something that I'm not?

[soda0289]

You are right @weirdpattern those examples I gave are invalid typescript. I was just reading the code and noticied rest paremeters were missing the type annotation conversion. I did not know initializers with the rest parameter were invalid, or that it had to be an array but that makes sense.

With the following code

function lll(...name: string[]): string {
        return name;
}

The output I get for function declation is

{ type: 'FunctionDeclaration',
  range: [ 203, 267 ],
  loc: { start: { line: 16, column: 0 }, end: { line: 18, column: 1 } },
  id:
   { type: 'Identifier',
     range: [ 212, 215 ],
     loc: { start: [Object], end: [Object] },
     name: 'lll' },
  generator: false,
  expression: false,
  async: false,
  params:
   [ { type: 'RestElement',
       range: [Object],
       loc: [Object],
       argument: [Object] } ],
  body:
   { type: 'BlockStatement',
     range: [ 243, 267 ],
     loc: { start: [Object], end: [Object] },
     body: [ [Object] ] },
  returnType:
   { type: 'TypeAnnotation',
     loc: { start: [Object], end: [Object] },
     range: [ 236, 242 ],
     typeAnnotation: { type: 'TSStringKeyword', range: [Object], loc: [Object] } } }

For the rest element

{ type: 'RestElement',
  range: [ 216, 233 ],
  loc:
   { start: { line: 16, column: 13 },
     end: { line: 16, column: 30 } },
  argument:
   { type: 'Identifier',
     range: [ 219, 223 ],
     loc: { start: [Object], end: [Object] },
     name: 'name' } }

I think type annotations are missing from the argument property of the RestElement node and would also need to have type annotations included.

[weirdpattern]

@soda0289 I think you are right. I will fix this today. Thanks!

[eslintbot]

LGTM

[weirdpattern]

@soda0289 ok, I've included rest arguments in this PR

[soda0289]

LGTM Thanks!

[nzakas]

LGTM, thanks!