How can I designate inner schemas as optional in Ajv?

Question

How can I designate inner schemas as optional in Ajv?

Here is a sample schema using ajv (v8.11.2)

import Ajv, { JSONSchemaType } from "ajv";

interface MyType {
    myProp?: OtherType;
}

interface OtherType {
    foo: string;
    bar: number;
}

const otherSchema: JSONSchemaType<OtherType> = {
    type: 'object',
    properties: {
        foo: { type: 'string', minLength: 1 },
        bar: { type: 'number' },
    },
    required: ['foo', 'bar'],
    additionalProperties: false
};

const mySchema: JSONSchemaType<MyType> = {
    type: 'object',
    properties: {
        myProp: otherSchema,
    },
    required: [],
    additionalProperties: false,
};

An error occurs:

Types of property '$ref' are incompatible. Type 'string | undefined' is not assignable to type 'string'. Type 'undefined' is not assignable to type 'string'.

The issue may be due to TypeScript not recognizing that myProp in mySchema could be undefined even though it is not in the required list.

Any suggestions on how to resolve this schema error?

typescript ajv

Answer 1

Answer №1

Follow these steps for success:

import { JSONSchemaType } from "ajv";

interface DifferentType {
  cat: string;
  dog: number;
}

interface YourType {
  yourProp?: DifferentType;
}

export const differentSchema: JSONSchemaType<DifferentType> = {
  type: "object",
  properties: {
    cat: { type: "string", minLength: 1 },
    dog: { type: "number" }
  },
  required: ["cat", "dog"],
  additionalProperties: false
};

export const yourSchema: JSONSchemaType<YourType> = {
  type: "object",
  properties: {
    // Place your objects inside "properties"
    yourProp: {
      ...differentSchema,
      nullable: true // Don't forget this nullable parameter!
    }
  },
  required: [],
  additionalProperties: false
};

Check out this live example:

https://codesandbox.io/s/ajv-schema-json-nested-qu9e7q?file=/src/schemas.ts

Answer 2

Follow these steps for success:

import { JSONSchemaType } from "ajv";

interface DifferentType {
  cat: string;
  dog: number;
}

interface YourType {
  yourProp?: DifferentType;
}

export const differentSchema: JSONSchemaType<DifferentType> = {
  type: "object",
  properties: {
    cat: { type: "string", minLength: 1 },
    dog: { type: "number" }
  },
  required: ["cat", "dog"],
  additionalProperties: false
};

export const yourSchema: JSONSchemaType<YourType> = {
  type: "object",
  properties: {
    // Place your objects inside "properties"
    yourProp: {
      ...differentSchema,
      nullable: true // Don't forget this nullable parameter!
    }
  },
  required: [],
  additionalProperties: false
};

Check out this live example:

https://codesandbox.io/s/ajv-schema-json-nested-qu9e7q?file=/src/schemas.ts

Answer 3

Answer №2

The issue seems to stem from the discrepancy between the type declared for myProp in your MyType and the object type set for that property in your schema. TypeScript is pointing out the type mismatch because OtherType is not the same as JSONSchemaType<OtherType>.

To resolve this, you can update your MyType as follows:

interface MyType {
  myProp?: JSONSchemaType<OtherType>;
}

While I may not be familiar with the ajv package or the JSONSchemaType type, I believe this adjustment should address the error you've encountered.

Answer 4

The issue seems to stem from the discrepancy between the type declared for myProp in your MyType and the object type set for that property in your schema. TypeScript is pointing out the type mismatch because OtherType is not the same as JSONSchemaType<OtherType>.

To resolve this, you can update your MyType as follows:

interface MyType {
  myProp?: JSONSchemaType<OtherType>;
}

While I may not be familiar with the ajv package or the JSONSchemaType type, I believe this adjustment should address the error you've encountered.

How can I designate inner schemas as optional in Ajv?

Answer №1

Answer №2

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