DEA-C02 · Question #57
Which callback function is required within a JavaScript User-Defined Function (UDF) for it to execute successfully?
The correct answer is B. processRow(). processRow() is the required callback because JavaScript UDFs in systems like Google BigQuery invoke it automatically for each row of input data - without it, the UDF has no entry point to process anything and will fail to execute. initialize() and finalize() are optional…
Question
Which callback function is required within a JavaScript User-Defined Function (UDF) for it to execute successfully?
Options
- Ainitialize()
- BprocessRow()
- Chandler()
- Dfinalize()
How the community answered
(17 responses)- B94% (16)
- C6% (1)
Explanation
processRow() is the required callback because JavaScript UDFs in systems like Google BigQuery invoke it automatically for each row of input data - without it, the UDF has no entry point to process anything and will fail to execute. initialize() and finalize() are optional callbacks used for setup before rows are processed and cleanup after all rows are processed, respectively; omitting them is valid. handler() is not a recognized UDF callback at all - it appears in other JavaScript contexts (like event listeners) but has no role in the UDF lifecycle.
Memory tip: Think of processRow() as the "heart" of a UDF - it's what actually does the work row by row, making it the only one that's non-negotiable.
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