allow custom data types to specify serialize function

[ahdinosaur]

hey 😄, i think it would be great if we could specify serialize functions for our custom data types.

my use case is for using big.js decimals as a custom data type where the representation as an object is not how i want the object serialized. i could write a custom serialize function for my model, but it seems like this information should be part of the data type definition.

how do we feel about this?

[latentflip]

So, this may change, but right now the way this is done for dates for example, is to store the serialized representation in the state object, and to reconvert it in the getter. serialize() on the state object will grab that internal representation.

So, date looks like (slightly simplified)

date: {
  set: function (newVal) {
    return {
      type: 'date',
      val: newVal.valueOf() //integer representing the date
    };
  },
  get: function (val) {
    return new Date(val);
  }
}

So, for big.js you could do something similar

decimal: {
  set: function (newVal) {
    if (newVal instanceof Big) {
      return {
        type: 'decimal',
        val: newVal.toF()
      };
    } else {
      return {
        type: typeof newVal,
        val: newVal
      }
    }
  },
  set: function (val) {
    return new Big(val);
  }
}

I think that should work, even if it's not the most obvious solution. I'm currently thinking about how all this datatype stuff works, and whether we can improve it, so thouhts welcomed! :)

[ahdinosaur]

thanks @latentflip, your solution works great. 😸 i'll see if i run into anything as i use it, but for now this pattern is what i needed.

cheers, 🍧

[ianwremmel]

I'd also like to see serialize() (and maybe deserialize()) separate from get (and set). I'm running into an issue where I want my client code to use Date objects, but my server only accepts ISODate strings. I can deal with it by overriding State#serialize(), but it feels more elegant to do it in State#dataTypes.