[GitHub] [arrow] shuhaowu opened a new issue, #34936: [JavaScript] Allow index access for `Table`, `RecordBatch`, and `Vector`

["shuhaowu (via GitHub)" <gi...@apache.org>]

shuhaowu opened a new issue, #34936:
URL: https://github.com/apache/arrow/issues/34936

   ### Describe the enhancement requested
   
   Certain codebases that previously uses row-oriented way to access data may wish to migrate to Arrow to save serialization and deserialization cost, and to be able to gain access to fast column-oriented operations. As it stands, Arrow is sort of a drop-in replacement to row-oriented data such as a JavaScript Array of objects. This is great to incrementally migrate legacy codebases to Arrow, as it is frequently infeasible to rewrite the application to use the column-oriented data access patterns. For most data, JavaScript-object-compatible and row-oriented access is already provided via the `StructRowProxy`. However, if the structs themselves include a `Vector`, existing code will break as it assumes the `Vector` object to behave like a JavaScript array, which it does not due to the lack of index access. An example of such a data structure is as follows:
   
   ```
   [
     {x: 1, y: [1, 2]},
     {x: 2, y: [2, 3]},
   ]
   ```
   
   In this case, with the Arrow JS library as it is, the API consumer is unable to get individual element of the `y` array via `table[i].y[j]`. Instead, the API consumer must use the API `table.get(i).y.get(j)`. In the situation where we are migrating a legacy code base to Arrow, this requires a large refactor of the entire codebase, which is infeasible in a short time. This negates the advantage of using Arrow as a drop-in replacement and prevents incremental migration of code to Arrow.
   
   Arrow should provide index access for the `Vector` object, as well as `Table` and `RecordBatch` for backward compatibility with JavaScript arrays.
   
   ### Component(s)
   
   JavaScript


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