Bigquery JS UDF Examples

bq_js_persitent_fun_with_ext_source.sql

-- Example of a persistent function that use libraries stored in Google Cloud Storage
-- Taken from https://cloud.google.com/bigquery/docs/reference/standard-sql/user-defined-functions
CREATE OR REPLACE FUNCTION dataset.myFunc(a FLOAT64, b STRING)
  RETURNS STRING
  LANGUAGE js
  OPTIONS (
    library=["gs://my-bucket/path/to/lib1.js", "gs://my-bucket/path/to/lib2.js"]
  )
  AS
"""
    // Assumes 'doInterestingStuff' is defined in one of the library files.
    return doInterestingStuff(a, b);
""";

SELECT myFunc(3.14, 'foo');

bq_js_set_diff_udf.sql

-- Example of a temporary function that does a set difference on two string arrays
CREATE TEMPORARY FUNCTION string_set_diff(arr1 ARRAY<STRING>, arr2 ARRAY<STRING>) 
RETURNS ARRAY<STRING> 
LANGUAGE js AS """
  let difference = arr1.filter(x => !arr2.includes(x));
  return difference
""";
SELECT string_set_diff(ARRAY ['foo', 'bar'], ARRAY ['baz', 'foo']);
                                                    
-- Results in unity array with value 'bar'