Iterator.prototype.some() example incorrectly claims a return value of false

[Hexstream]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/some

What specific section or headline is this issue about?

Using some()

What information was incorrect, unhelpful, or incomplete?

// false should be // true.

What did you expect to see?

Correct return value.

Do you have any supporting links, references, or citations?

No response

Do you have anything more you want to share?

No response

MDN metadata

Page report details

• Folder: en-us/web/javascript/reference/global_objects/iterator/some
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/some
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/javascript/reference/global_objects/iterator/some/index.md
• Last commit: a71768c
• Document last modified: 2024-11-16T07:26:34.000Z

[Josh-Cena]

This line:

console.log(fibonacci().take(10).some(isPositive)); // false

Should be changed to:

console.log(fibonacci().take(10).some(isNegative)); // false

[Hexstream]

It could be that, in which case we can delete const isPositive = (x) => x > 0;.

Or the line could instead be changed to:

console.log(fibonacci().some(isPositive)); // true

This is perhaps better due to better "symmetricality" of examples:

console.log(fibonacci().some(isPositive)); // true
console.log(fibonacci().some(isNegative)); // Never completes

VS

console.log(fibonacci().take(10).some(isNegative)); // false
console.log(fibonacci().some(isNegative)); // Never completes

However, in that case the isEven part becomes redundant and could be deleted.
We should still have an example of returning false from some, though...

So the full example minus the fibonacci definition could be:

const isNegative = (x) => x < 0;
const isPositive = (x) => x > 0;
console.log(fibonacci().take(10).some(isNegative)); // false
console.log(fibonacci().some(isPositive)); // true
console.log(fibonacci().some(isNegative)); // Never completes

In other words, this combines your proposed line, my proposed line and removing the now redundant isEven part.

[Josh-Cena]

The goal of this example is to demonstrate what happens if nothing matches: a finite iterator returns false, while an infinite iterator never completes. The "something matches" case is already covered by the previous isEven example.

This was a simple typo of mine when I copied the Iterator.prototype.every page.

[Hexstream]

Whatever works. :)