Migrate core/tooltip.js to goog.module syntax

[gonfunko]

The basics

• I branched from goog_module
• My pull request is against goog_module
• My code follows the style guide
• My code is presented in the form suggested in the module
  conversion guide
• I have run npm test.

The details

Resolves

Part of #5026

Proposed Changes

Converts core/tooltip.js to goog.module with ES6 const/let.

[cpcallen]

Generally fine, but I have a few questions.

[cpcallen]

Are we expecting that developers will want to modify this value?

[gonfunko]

Checked with Beka and she wasn't aware of and couldn't find anyone that was. I take the all-caps to imply that it was intended as a constant as well.

[cpcallen]

I guess the question then is: does it need to be exported? I don't see reference to it anywhere outside this file (but maybe it's referenced outside this repo?)

[gonfunko]

Looks like it's used in blockly-samples: https://github.com/google/blockly-samples/blob/1be2b748414ef147c8f7d657fa440442c0ef49a8/plugins/block-extension-tooltip/src/tooltip_monkey_patch.ts

[BeksOmega]

That's kind of annoying. First party plugins aren't supposed to monkey patch according to our own criteria. Sucks that this has to be made public because of that :/

[cpcallen]

This doesn't look correct. If we're exporting visible, presumably external code wants to know the current value of the flag, not just the initial value.

See the style guide under "Mutability of exports" for how to deal with this (but maybe for now exports.visible needs to be an actual getter, for backwards compatibility.)

(Also: perhaps add @type {boolean} to the JSDoc?)

[gonfunko]

Updated this (and DIV) following the pattern we've settled on.

[cpcallen]

I'm un-assigning this from myself for now but feel free to reassign when you want a re-review.

[cpcallen]

I think this is fine, but I did have one niggle.

[cpcallen]

I guess the question then is: does it need to be exported? I don't see reference to it anywhere outside this file (but maybe it's referenced outside this repo?)

[cpcallen]

This is being overwritten by a call to Object.defineProperties below, and somehow I dislike that, though I can't articulate exactly why.

It this the easiest way to get the correct documentation and type info associated with the exported name? I think I'd prefer a pure declaration, even though we'd be repeating the JSDoc:

/**
 * Is a tooltip currently showing?
 * @type {boolean}
 * @deprecated September 2021
 */
exports.visible;

Or even—since it's deprecated and a compiler warning might encourage people to migrate—just:

/** @deprecated September 2021 */
exports.visible;

("This is not important; wontfix" might be reasonable answer.)

[gonfunko]

Done!