Json Question posted in
Our archive of expertly curated questions and answers provides insights and solutions to common problems related to this popular data interchange format. From parsing and manipulating JSON data to integrating it with various programming languages and web services, our archive has got you covered. Start exploring today and take your JSON skills to the next level

Json – ajv schema validation fails when working with array types

I’m using ajv to validate a JSON instance using a fairly simple schema, but that is failing on the array type with the following message:

"this must be equal to one of the allowed values"

Problem is, my value is one of the allowed values. This seems like such a simple problem but I’ve not yet found a solution. Here’s my code:

const Ajv = require("ajv");
const ajv = new Ajv();

const schema = {
  type: "object",
  properties: {
    count: { type: "integer" },
    name: { type: "string" },
    bass: {
      type: "array",
      items: {
        type: "string",
      },
      enum: ["Ambush Custom Bass", "MTD", "Ken Smith", "Sadowsky"],
    },
  },
  required: ["count"],
};

const validate = ajv.compile(schema);

const data = {
  count: 1,
  name: "Andy",
  bass: ["MTD"],
};

const valid = validate(data);

console.log("valid: ", valid);

if (!valid) console.log(validate.errors);

Thanks for your help.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Well, as usual, I had to first ask the question to the masses so I could figure it out on my own. I don't know if it's the right way, but here's what I did:

    First, remove the keyword for enum, like so:

    ajv.removeKeyword("enum");

    Next, add the enum keyword back, and with it, your custom validation function:

    ajv.addKeyword({
  keyword: "enum",
  validate: (schema, data, value, other) => {
    // custom validation goes here
  }
});

    Finally, I found that the validate function here doesn't give you the option of adding detailed error messaging (or, if it does, I couldn't figure out how to do it), so I created an error array, then pushed entries into that array, with each entry being an object that includes other.instancePath. Then when iterating through the validation.errors array, I combine the more detailed messaging with ajv's errors so I can have custom error messaging along with the error details ajv provides. I hope that makes sense; if not, give me a holler, and I'll further explain.


  2. 0

    there is actually a much simpler solution: add the enum values under items field:

    ...
const schema = {
  type: "object",
  properties: {
    count: { type: "integer" },
    name: { type: "string" },
    bass: {
      type: "array",
      items: {
        type: "string",
        enum: ["Ambush Custom Bass", "MTD", "Ken Smith", "Sadowsky"],
      },
    },
  },
  required: ["count"],
};
...

    This way you don’t need to remove/add enum keyword

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search