Print class property definite assignment assertions

[lokshunhung]

Resolves #1012

This PR makes the printer aware of definite property in ClassProperty AST node, printing ! when true

[eventualbuddha]

Thanks! Mind adding a test?

[lokshunhung]

@eventualbuddha Sure, could you point me to the location where I should put this?

[eventualbuddha]

@eventualbuddha Sure, could you point me to the location where I should put this?

Maybe here?

[lokshunhung]

@eventualbuddha I checked test/typescript.ts and it seems that it contains tests for checking syntax validity and reprinting

I put the tests inside test/printer.ts below this

[lokshunhung]

I had to use Object.assign(b.classProperty(...), { definite: true }) instead of b.classProperty.from(...) in the test, as it seems that ast-types does not handle the definite property in ClassProperty nodes 😅

import * as assert from "assert";
import * as ast from "ast-types";

const b = ast.builders;

const n1 = Object.assign(
  b.classProperty(
    b.identifier("key"),
    null
  ),
  { definite: true }
);

const n2 = b.classProperty.from({
  key: b.identifier("key"),
  value: null,
  definite: true,
});

assert.deepStrictEqual(n1, n2);

Expected values to be strictly deep-equal: 
+ actual - expected ... Lines skipped 
 
  { 
    access: undefined, 
    comments: null, 
    computed: false, 
+   definite: true, 
    key: { 
... 
    value: null, 
    variance: null 
  }