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In the TypeScript definition:
```
interface Generator<T = unknown, TReturn = any, TNext = any>
```
setting `TNext` to `null` can cause a typing error when `strictNullChecks` is enabled. For example:
```
error TS2763: Cannot iterate value because the 'next' method of its iterator expects type 'null', but for-of will always send 'undefined'.
288 for (const d of data) {
~~~~
```
(from uwdata/mosaic#792 (comment))
While the strict type for `TNext` should technically be `undefined`, since this generator function does not make use of the value passed to `.next()`, it's more flexible to keep it as `any`. This is the default type and helps avoid blocking compatibility with libraries that may pass a value to `.next()` (even if that value is unused in this generator).
Member
|
Makes sense. At some point we should improve the types here so that the table is more strictly typed (we did a pretty good job with having strict types in the arrow js library). |
domoritz
approved these changes
Jun 17, 2025
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In the TypeScript definition:
setting
TNexttonullcan cause a typing error whenstrictNullChecksis enabled. For example:(from uwdata/mosaic#792 (comment))
While the strict type for
TNextshould technically beundefined, since this generator function does not make use of the value passed to.next(), it's more flexible to keep it asany. This is the default type and helps avoid blocking compatibility with libraries that may pass a value to.next()(even if that value is unused in this generator).