source property is missing from return type of Intl formatRangeToParts methods

[devongovett]

Bug Report

The source property is missing on the returned parts from the formatRangeToParts method of Intl.DateTimeFormat and Intl.NumberFormat. See for example https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/formatRangeToParts.

🔎 Search Terms

formatRangeToParts

🕗 Version & Regression Information

all

⏯ Playground Link

I can't get the playground to use es2021 as the target. It just reverts back to ES3.

💻 Code

let formatter = new Intl.DateTimeFormat('en-US');
formatter.formatRangeToParts(new Date(), new Date())[0].source

🙁 Actual behavior

Error, source does not exist

🙂 Expected behavior

No error, source exists.