Interface RecordV2Delta

A RecordV2Delta describes the differences between two RecordV2 values. Unlike a binary delta, a structural delta can be queried to determine its effect. The RecordV2Delta.changes method provides details of which values have changed.

An instance can be created from two RecordV2 values using RecordV2.diff.

RecordV2Deltas are useful for identifying small changes to complex RecordV2 values. Here is an example of how to use this class to filter interesting changes from a value stream.

Example:

var datatype = diffusion.datatypes.recordv2();

session.addStream("topic", datatype).on('value', (path, spec, newValue, oldValue) => {
    var schema = datatype.parseSchema(spec.properties.SCHEMA);

    newValue.diff(oldValue).changes(schema).forEach((change) => {
        if (change.fieldName === "address") {
            // Do something with the changed address
            console.log(newValue.getFields());
        }
    });
});

author

DiffusionData Limited

since

6.0

see

diffusion.datatypes.RecordV2.diff