Property 'difference' does not exist on type 'Set'

🔎 Search Terms

is:issue set difference does not exist

🕗 Version & Regression Information

I tested this on the Nightly TypeScript version, 5.7, 5.6, etc.

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about FAQ (For Issue Filers)

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.7.0-dev.20240919#code/PTAEAsBdIBwZwFwgCYFMBuqA2B7GqAnAOgFscAvASyywEMicCBzYVAOwFoBVAZWGRwBjOMADqqAEbAAUrXS0eggpRiRgAJVQAzQu0GpgAcVwTaWAPoB5CQCtUgyCJ6o1ySlp0E9qACQAGAChBHDY4SFAcZGQ4UABeUDZUAHdQZ0gACgBtAEYAGlAAZnyAVnyAdnyATgBdAEoAbiCQsNA4AEcAV1ovGPjElLSsvNAAFiq6xuDQnCxUIlwmdMjoojcPXTZ9dPauntqG0BBUl3SC2tAAb0KS8tAAXyA

💻 Code

// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/difference$0
const odds = new Set([1, 3, 5, 7, 9]);
const squares = new Set([1, 4, 9]);
console.log(odds.difference(squares)); // Set(3) { 3, 5, 7 }

🙁 Actual behavior

Property 'difference' does not exist on type 'Set<number>'.ts(2339)

TypeScript does not recognize the property.

🙂 Expected behavior

I expected TypeScript to recognize the property, since:

1. MDN confirms it is widely available
2. Add types for stage 3 "set methods" proposal #57228 and add types for set methods proposal #57230 seem to have accepted and merged this back in May.

Why is the compiler still showing that it isn't recognized?

Additional information about the issue

No response

[itsramiel]

@occassionally why did you close this? How did you resolve the issue?

Rami Elwan (@itsramiel) I closed it because I tested it and the functions aren't available on Node 20.16.0, and possibly not in JavaScript itself either (still in draft phase, I didn't test specifically), so I figured this was why TypeScript didn't recognize it. I just wrote my own implementations.

I re-opened it though, so we can get the maintainers' feedback.

[jcalz]

Make sure your --target is for a version of JavaScript that supports this. In this case, esnext: playground link