createAjvInstance.ts

import Ajv, { Options } from "ajv";
import addFormats, { FormatsPluginOptions } from "ajv-formats";
import isObject from "lodash/isObject";

import { CustomValidatorOptionsType } from "./types";

export const AJV_CONFIG: Options = {
  allErrors: true,
  multipleOfPrecision: 8,
} as const;
export const COLOR_FORMAT_REGEX =
  /^(#?([0-9A-Fa-f]{3}){1,2}\b|aqua|black|blue|fuchsia|gray|green|lime|maroon|navy|olive|orange|purple|red|silver|teal|white|yellow|(rgb\(\s*\b([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\b\s*,\s*\b([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\b\s*,\s*\b([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\b\s*\))|(rgb\(\s*(\d?\d%|100%)+\s*,\s*(\d?\d%|100%)+\s*,\s*(\d?\d%|100%)+\s*\)))$/;
export const DATA_URL_FORMAT_REGEX =
  /^data:([a-z]+\/[a-z0-9-+.]+)?;(?:name=(.*);)?base64,(.*)$/;

/** Creates an Ajv version 8 implementation object with standard support for the 'color` and `data-url` custom formats.
 * If `additionalMetaSchemas` are provided then the Ajv instance is modified to add each of the meta schemas in the
 * list. If `customFormats` are provided then those additional formats are added to the list of supported formats. If
 * `ajvOptionsOverrides` are provided then they are spread on top of the default `AJV_CONFIG` options when constructing
 * the `Ajv` instance. With Ajv v8, the JSON Schema formats are not provided by default, but can be plugged in. By
 * default, all formats from the `ajv-formats` library are added. To disable this capability, set the `ajvFormatOptions`
 * parameter to `false`. Additionally, you can configure the `ajv-formats` by providing a custom set of
 * [format options](https://github.com/ajv-validator/ajv-formats) to the `ajvFormatOptions` parameter.
 *
 * @param [additionalMetaSchemas] - The list of additional meta schemas that the validator can access
 * @param [customFormats] - The set of additional custom formats that the validator will support
 * @param [ajvOptionsOverrides={}] - The set of validator config override options
 * @param [ajvFormatOptions] - The `ajv-format` options to use when adding formats to `ajv`; pass `false` to disable it
 */
export default function createAjvInstance(
  additionalMetaSchemas?: CustomValidatorOptionsType["additionalMetaSchemas"],
  customFormats?: CustomValidatorOptionsType["customFormats"],
  ajvOptionsOverrides: CustomValidatorOptionsType["ajvOptionsOverrides"] = {},
  ajvFormatOptions?: FormatsPluginOptions | false,
  AjvClass: typeof Ajv = Ajv
) {
  const ajv = new AjvClass({ ...AJV_CONFIG, ...ajvOptionsOverrides });
  if (typeof ajvFormatOptions !== "boolean") {
    addFormats(ajv, ajvFormatOptions);
  }

  // add custom formats
  ajv.addFormat("data-url", DATA_URL_FORMAT_REGEX);
  ajv.addFormat("color", COLOR_FORMAT_REGEX);

  // add more schemas to validate against
  if (Array.isArray(additionalMetaSchemas)) {
    ajv.addMetaSchema(additionalMetaSchemas);
  }

  // add more custom formats to validate against
  if (isObject(customFormats)) {
    Object.keys(customFormats).forEach((formatName) => {
      ajv.addFormat(formatName, customFormats[formatName]);
    });
  }

  return ajv;
}