Feature request: Date support in forValue(..)

[SanderElias]

See this sample:

import avro from 'avsc';

const data = {
  city: 'Cambridge',
  date: new Date(),
};

const type = avro.Type.forValue(data);
const buf = type.toBuffer(data);
const result = type.fromBuffer(buf)
console.log(JSON.stringify(data)===JSON.stringify(result))
/** retuns false! */
console.log(result);
/** { city: 'Cambridge', date: {} } */

I would expect that dates would be handled properly. Or did I misunderstood something?
I'm willing to create a PR for this if there is an interest.

[mtth]

Hi @SanderElias. By default, forValue only supports the standard Avro types. You can extend type inference via the valueHook option, often in combination with a logical type.

For example, to infer Dates:

/** Minimal date logical type. */
class DateType extends avro.types.LogicalType {
  _fromValue(val) { return new Date(val); }
  _toValue(date) { return date instanceof Date ? +date : undefined; }
}

// Type where all `Date` fields are represented as `DateType`s.
const type = avro.Type.forValue(data, {
  valueHook: (val, opts) => {
    if (val instanceof Date) {
      return new DateType({type: 'long', logicalType: 'timestamp-millis'}, opts);
    }
    // Optionally add more logic here... Returning `undefined` falls back to
    // default inference.
  },
});
console.log(type.clone(data)); // { city: 'Cambridge', date: 2020-10-19T15:52:29.621Z }