refactor(lsp): refactor completions and add tests

[kitsonk]

This refactor is to give us a more solid base to build on for import completions.

It refactors some code and adds a completion resolver, plus some tests.

[kitsonk]

These give us default values if they aren't sent by the client, this makes it a lot easier dealing with the values.

[lucacasonato]

Looks great. Tested it locally, and optional chaining completions now work correctly. 👍

[lucacasonato]

Why not use CompletionItemKind::Constant for this? This is what sourcegraphs' tsc LSP does. Did you align this to VSC impl instead?

[kitsonk]

Yes, I will double check that I didn't make a mistake though.

[kitsonk]

Nope, that is the way it is in VSCode 🤷 :

private static convertKind(kind: string): vscode.CompletionItemKind {
  switch (kind) {
    case PConst.Kind.primitiveType:
    case PConst.Kind.keyword:
      return vscode.CompletionItemKind.Keyword;

    case PConst.Kind.const:
    case PConst.Kind.let:
    case PConst.Kind.variable:
    case PConst.Kind.localVariable:
    case PConst.Kind.alias:
    case PConst.Kind.parameter:
      return vscode.CompletionItemKind.Variable;

    case PConst.Kind.memberVariable:
    case PConst.Kind.memberGetAccessor:
    case PConst.Kind.memberSetAccessor:
      return vscode.CompletionItemKind.Field;

    case PConst.Kind.function:
    case PConst.Kind.localFunction:
      return vscode.CompletionItemKind.Function;

    case PConst.Kind.method:
    case PConst.Kind.constructSignature:
    case PConst.Kind.callSignature:
    case PConst.Kind.indexSignature:
      return vscode.CompletionItemKind.Method;

    case PConst.Kind.enum:
      return vscode.CompletionItemKind.Enum;

    case PConst.Kind.enumMember:
      return vscode.CompletionItemKind.EnumMember;

    case PConst.Kind.module:
    case PConst.Kind.externalModuleName:
      return vscode.CompletionItemKind.Module;

    case PConst.Kind.class:
    case PConst.Kind.type:
      return vscode.CompletionItemKind.Class;

    case PConst.Kind.interface:
      return vscode.CompletionItemKind.Interface;

    case PConst.Kind.warning:
      return vscode.CompletionItemKind.Text;

    case PConst.Kind.script:
      return vscode.CompletionItemKind.File;

    case PConst.Kind.directory:
      return vscode.CompletionItemKind.Folder;

    case PConst.Kind.string:
      return vscode.CompletionItemKind.Constant;

    default:
      return vscode.CompletionItemKind.Property;
  }
}