Not possible to have optional object property compatible with both Closure Compiler and Intellisense

• VSCode Version: 1.32.3 x64
• OS Version: Ubuntu 18.04

Steps to Reproduce:

1. Enable "checkJs": true in jsconfig.json.
2. Create a Javascript file:

class A {

  /**
   * @param {{field: string|undefined}} obj 
   */
  constructor(obj) {
    this.obj = obj;
  }
}

let a = new A({});

Results in this error:

Adding error text here for duplicate detection:
Argument of type '{}' is not assignable to parameter of type '{ field: string; }'.
Property 'field' is missing in type '{}' but required in type '{ field: string; }' .ts(2345)

Does this issue occur when all extensions are disabled?: Yes

Expected behaviour:
Some way to mark object properties as optional compatible both with Closure Compiler and VsCode intellisense. Either through @typedef, through structural interfaces with @record, direct @param notation using string|undefined, or something similar.

This notation works fine today, but it is not recognized by Closure Compiler. It is debatable whether this is an issue with Intellisense or lacking support from Closure Compiler.

class A {

  /**
   * @param {AParam} obj 
   */
  constructor(obj) {
    this.obj = obj;
  }
}

/** @typedef {{field?: string|undefined}} */
var AParam;
let a = new A({});

Start with the jsconfig.json reproduction using checkJs and the JSDoc @param and @typedef forms shown in the report. Compare how TypeScript handles the optional-property notation with the stated Closure Compiler compatibility requirement. Done means a supported notation allows new A({}) without the reported missing-property error while remaining compatible with Closure Compiler.