Objection.js: JSON Schema Type Conversion / Coercion

[zjr]

Hi there. I've been looking through the docs & existing issues but am having a hard time finding information about this.

Is there a standard way to handle type coercion with JSON Schema?

For instance, I have a select input with integer values but by simple virtue of being a select input the values will always be strings. In my DB, however, they need to be integers. If I try to input this data get a ValidationError. Checking every place some front end JavaScript messes with a type would be rather cumbersome.

Most general way I have found so far is to define a $parseJson on a BaseModel, look for keys that should be numbers, and make a conversion there. Is the generally The Way or is there a more built in approach to this? If there isn't would you _want_ a built in approach?

Thanks for reading.

[koskimas]

Hi,

Objection uses ajv as the json schema validator. You can enable the coerceTypes option.

This is how you can override ajv options:

class BaseModel extends Model {
  static createValidator() {
    return new AjvValidator({
      onCreateAjv: ajv => {},
      options: {
        allErrors: true,
        validateSchema: false,
        ownProperties: true,
        v5: true,
        coerceTypes: true // <--- !!!
      }
    });
  }
}

const { BaseModel } = require('./base-model')

class Person extends BaseModel {
  ...
}

Let me know if this works

[zjr]

That works fantastically, thank you!