kentkwu opened a new pull request, #510:
URL: https://github.com/apache/arrow-js/pull/510
## Summary
Infers arrays of typed arrays as proper Arrow types, so
`vectorFromArray([uint8Array, ...])` produces a `Binary` vector instead of a
struct with one `Float64` field per byte.
### The problem
Type inference treated typed arrays as plain objects and built a struct from
their index keys. An array of 16-byte `Uint8Array` values became `Struct<{0:
Float64, ..., 15: Float64}>` instead of `Binary`. The output was also lossy:
values of different lengths were padded with nulls to the longest one, and the
static type resolved to `never`.
### Behavior change
This changes the inferred type for these inputs, but it's a bug fix: the old
output didn't preserve the input values and didn't match its own static type.
Code that needs a specific type can still pass one explicitly to
`vectorFromArray`.
### Changes
- `vectorFromArray` infers `Uint8Array` (and Node `Buffer`) elements as
`Binary`, and other typed arrays as `List` of their element type (e.g.
`Int32Array` → `List<Int32>`)
- `tableFromArrays` and `tableFromJSON` pick this up for columns and struct
fields, so `tableFromArrays({ values: [[bytes, bytes]] })` gives `List<Binary>`
- `JavaScriptArrayDataType` resolves to the same types at compile time
instead of `never`
- Mixed typed array kinds and `DataView` elements throw the existing
"explicit type declaration expected" error
## Test Plan
- [x] `npx jest -c jestconfigs/jest.src.config.js test/unit`
- [x] `npx eslint src/factories.ts src/interfaces.ts
test/unit/vector/vector-tests.ts`
- [x] Checked inferred static types for `Uint8Array`, `Buffer`,
`Int32Array`, `Uint8ClampedArray`, and `BigInt64Array` with `tsc`
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