Generated attributes: Pass current model to attribute default function.

[vangorra]

It would be awesome if we could specify a default function for an attribute and get the current instance of the model as a parameter. That would allow us to populate the secondary index in a better way.

const schema = {
  _id: String,
  country: String,
  state: String,
  surName: String,
  surNameIndex: {
    index: {
      default: model => {
        return `${model.country}_${model.state}_${model.surName}`;
      }
    }
  }
}

Seems passing the model here would do the trick:
https://github.com/automategreen/dynamoose/blob/108fcaa91fc1785dc4d3623231f6b7a16f877dc4/lib/Attribute.js#L280

More generically however, having a forceDefault boolean for the attribute to ensure the default is applied every time would also be useful. This would ensure the secondary index data is properly updated when the data is persisted.

[brandongoode]

Passing the model sounds like a great idea. Want to submit it as a PR?

Not sure I follow the forceDefault. Would this overwrite the value with the default, regardless of if there's currently a value?

Also, default would not be in the index. It should be applied directly to the attribute:

const schema = {
  _id: String,
  country: String,
  state: String,
  surName: String,
  surNameIndex: {
    index: true,
    default: model => {
      return `${model.country}_${model.state}_${model.surName}`;
    }
  }
}

[vangorra]

Yep. I'll submit the pr. Yes, force default would always overwrite the value on attribute value on the model. The idea here is to have a field that is flagged as an index and remains up to date. This would help keep the index updated based on the previous example. On Tue, Apr 11, 2017, 6:41 PM Brandon Goode <notifications@github.com> wrote: Passing the model sounds like a great idea. Want to submit it as a PR? Not sure I follow the forceDefault. Would this overwrite the value with the default, regardless of if there's currently a value? Also, default would not be in the index. It should be applied directly to the attribute: const schema = { _id: String, country: String, state: String, surName: String, surNameIndex: { index: true, default: model => { return `${model.country}_${model.state}_${model.surName}`; } } } — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#124 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABq9MiRJOcepFwaakpixV8r0DSeMv17tks5rvCvhgaJpZM4M5kiY> .

[troyswanson]

Is the idea for the generated value be stored in the DynamoDB table?

[vangorra]

@troyswanson Yes.

[troyswanson]

Would it be possible for something like #120 (comment) to be included with this?

[vangorra]

That looks out of scope of what I'm trying to accomplish here.

[troyswanson]

Fair enough.