keep_field

The keep_field processor keeps only the specified field, or fields, on a DataEntity or DataWindow and removes all others. It is the inverse of drop_field.

Usage

Keep only the specified field on a document

Example of a job using the keep_field processor

{
    "name" : "testing",
    "workers" : 1,
    "slicers" : 1,
    "lifecycle" : "once",
    "assets" : [
        "standard"
    ],
    "operations" : [
        {
            "_op": "test-reader"
        },
        {
            "_op": "keep_field",
            "field": "name"
        }
    ]
}

Here is a representation of what the processor will do with the configuration listed in the job above

const data = [
    DataEntity.make({ name: 'lilly', otherField: 1 }),
    DataEntity.make({ name: 'willy', otherField: 2  }),
    DataEntity.make({ name: 'billy', otherField: 3  }),
    DataEntity.make({ otherField: 4  }),
]

const results = await processor.run(data);

results = [
    { name: 'lilly' },
    { name: 'willy' },
    { name: 'billy' },
    { },
]

Parameters

Configuration	Description	Type	Notes
_op	Name of operation, it must reflect the exact name of the file	String	required
field	Name of field, or array of field names, to keep; all other fields are removed	String or String[]	required, no default