typescriptajv

Error: strict mode: unknown keyword: \"elements\"

AJV v8.17.1 has been working for validations in our project for a while, but we had never used it for an array type.

We recently added the "codes" array to this object:

{"name":"a","codes":["A01"]}

And now when the AJV "compile" method is hit, it is throwing this error:

strict mode: unknown keyword: \"elements\"

Here is the validation code (TS compliant in our VS Code project):

import { JTDSchemaType } from 'ajv/dist/core';
import Ajv from 'ajv';

type TempDetails = {
  name: string;
  codes: string[];
};

type JTDTempDetailsCreateRequestSchema = JTDSchemaType<TempDetails>;

const jtdTempDetailsCreateRequestSchema: JTDTempDetailsCreateRequestSchema = {
  properties: {
    name: { type: 'string' },
    codes: { elements: { type: 'string' } },
  },
};

const ajv = new Ajv();

const validate = ajv.compile<TempDetails>(jtdTempDetailsCreateRequestSchema);

if (!validate(untypedClass)) 
    throw new BadRequest(`Invalid Request: ${JSON.stringify(validate.errors)}`);
Solution

  • It turns out that { elements: { type: 'string' } }

    is correct per the docs: https://ajv.js.org/json-type-definition.html#elements-form

    but an auto-import occurred that resulted in the wrong import path being used.

    The incorrect import led to the wrong AJV validation being used.

    This caused confusion since the error only occurred for the array and not for the first line name: { type: 'string' }