validate-json-by-json-schema-action/src/validation.ts

import Ajv from "ajv";

export const validateJson = async (jsonFileContent: string): Promise<void> => {
  const jsonObject = JSON.parse(jsonFileContent);

  const schema = jsonObject["$schema"];
  if (!schema) {
    throw new Error("No schema found in JSON file.");
  }

  const schemaUrl = new URL(schema);

  const schemaContent = await fetch(schemaUrl.toString());
  const schemaText = await schemaContent.text();
  const schemaObject = JSON.parse(schemaText);

  const validator = new Ajv({
    strict: false,
  });
  const validate = validator.compile(schemaObject);
  const isValid = validate(jsonObject);
  if (!isValid) {
    throw new Error(`JSON file is not valid: ${validator.errorsText()}`);
  }
};