Adding globalThis about hermes

[avp]

d088f6f adds this.

[ljharb]

globalThis is the only standard JS global :-) the others are part of node or browsers.

[avp]

While globalThis isn't part of the standard yet (still in Stage 3 of the TC39 proposal process), it's already gained some amount of adoption and it seems reasonable to plan to add it to Hermes. We'll work on adding the property to the global object soon.

If you need access to the global object before globalThis is added to Hermes, you can use the Function constructor (which will be a little slower but should produce the correct output):

let global = (new Function('return this'))();

[ljharb]

@avp it's shipping in every browser https://twitter.com/mathias/status/1151140681374547969 so the stage isn't really relevant; it'll be stage 4 relatively soon. Glad to hear you're adding it :-)

[dulinriley]

It’s a shame that globalThis is a property that is writable, if it was a keyword we could compile it to GetGlobalObject in HBC.

[ljharb]

@dulinriley see item 2: https://github.com/tc39/proposal-global/blob/master/NAMING.md#constraints