Clarification of how to use nested schemas/models

[michaelsorich]

I am having a little difficulty understanding how to properly use nested schemas. In the objectschema example I see that there is a nested schema (the field books has a type of [bookSchema]) in the user schema. I am clear on defining the schema but I am not sure how to use this operationally in vue.

For example if I have a form in the template which enables editing of the details of all books in addition to the user details.

1. if I wish to have a button for adding additional books how do I code for this.
   e.g. my guess would be to use something like this.user.books.push({ title: 'True Detective' }), but this does not seem to work properly.

2. I also am having some issue with v-model on the nested models.
   e.g. I am attempting to display fields for all the nested models. In terms of the user/book example it would be something like this for the first book in the array

{{ user.books[0].$title.errors | firstMessage }} I find that the user.books[0].title value of the model is not updated when I change the value in the form field (e.g. if I include {{ user.books[0].title value }} in the template to track this) and hence the rest of the methods/properties (e.g. hasErrors, errors) are not updated either. If I use a simple data object instead of the schema object this issue does not occur. I notice that when I change the value of a form field bound to a field such as user.name it triggers the user.books[0].title value to be updated such that it matches what is in the form field. Any insight into what I am doing wrong would be appreciated.

[Kristijan Sedlak]

I'm about to start writing an example for you. I just need some information:

• How does your form structure look like?
• Are you using sub-components in your form?

[michaelsorich]

Thanks - this would be much appreciated.

I currently have a single component which focuses on editing the model (including its nested models). The template contains a single form containing simple fields of the parent model (using html input fields with v-model to bind the appropriate field similar to the example in the vue-contextable README.md), as well fields for each nested models in the array holding the nested models. I have been displaying the same set of fields for each instance of the nested model by iterating over nested models in the array using v-for (at the moment I have each nested model displayed as a row of a table). Next to the collection of fields for each nested model I have button to delete the nested model from the array (delete row from the table). I also have button to add an new nested model to the end of the array (i.e. add row to the bottom of the table in the form).

[Kristijan Sedlak]

Hum... it seams that Vue is not tracking changes on class instances but it could also be a bug in the plugin. I'll investigate so don't worry, we'll find a solution soon. I also asked for help here so please be patient.

[Kristijan Sedlak]

Here is what I came up with:

1. Since Vue.js doesn't recommend modifying a model structure at runtime, the easiest solution to fix this immediatelly is to set the defaultValue of each nested field to a non-null value as shown in the example below. This will deeply construct model structure before making the model reactive.

export default new Schema({
  fields: {
    ...
    book: {
      type: bookSchema,
      defaultValue: {} // THIS
    },
    books: {
      type: [bookSchema],
      defaultValue: [{}] // THIS
    }
  }
});

2. I've upgraded this plugin with a new modelData configuration option which pre-populates a model (preferred way).

export default {
  contextable: {
    validate: [
      { 
        ...
        modelData: {},
      }
    ]
  },
  ...
}

3. Two new reactive methods are also available - $build and $populate.

// using the $build method
export default {
  contextable: {
    ...
  },
  beforeCreate () {
    this.user.book = {title: 'asdasd'}; // sets field's data but removes reactivity
    this.user.books = [{title: 'asdasd'}]; // sets field's data but removes reactivity
    this.user.$build(); // rebuilds model reactivity
  }
}

// using the $populate method
export default {
  contextable: {
    ...
  },
  beforeCreate () {
    this.user.$populate({ // sets model fields and runs $build method
      name: null,
      book: {},
      books: [{}]
    });
  }
}

4. The new $build method will help you build a form with dynamic fields as well. See the example for details.

Features have been published and a new version of this package is now available for download. Please let me know if this works for you.

[Kristian Mandrup]

Cool :)