How to use property names in error messages with AJV errors

user_856498 0
Viewed 692

I am using ajv-errors with ajv v8 - According to docs I should be able to use a pointer to reference the field name but my attempts are failing with errors such as: Cannot access property/index 0 levels up, current level is 0

Example schema:

{
  $schema: "http://json-schema.org/draft-07/schema#",
  type: "object",
  additionalProperties: false,
  properties: {
    name: { type: "string" }
  },
  required: ["name"],
  errorMessage: {
   required:  'Field ${0#} is so required'
  }
}

Any ideas? I could probably use an absolute pointer but am not sure what data this is actually referring to in order to create a path.

ajv jsonschema javascript
1 Answers

0# is a relative json pointer for the current members name or array index.

ajv-errors bases this lookup on the { field: value } data it is validating rather than somewhere in the schema.

So inside a property errorMessage you have access to an object 1 level up:

{
  type: "object",
  properties: {
    named: {
      type: "string",
      errorMessage: {
        type: 'Field ${0#} is so ${1}', // 'Field "named" is so {"named":2}'
      },
    },
  },
}

It appears for required, there is no field or value so no data to lookup.

const schema = {
  type: "object",
  properties: {
    name: {
      type: "string",
    },
  },
  required: ["name"],
  errorMessage: {
    required: {
      name: 'Field "name" is so ${0}', // 'Field "name" is so {}'
    }
  },
}

You can add an explicit message for each field as above.

user_13186940
Related