How to use the jsonschema.Validator.prototype function in jsonschema

public validate(instance: any, schema: Schema): ValidatorResult {
        Validator.prototype.customFormats.BigNumber = function(input) {
            const regex = RegExp("^\\d+(\\.\\d+)?$");
            // This allows undefined inputs, e.g. salt is not present sometimes.
            return input === undefined || (input.isBigNumber && regex.test(input.toString()));
        };

        Validator.prototype.customFormats.wholeBigNumber = function(input) {
            const regex = RegExp("^\\d+$");
            return input && input.isBigNumber && regex.test(input.toString());
        };

        return this._validator.validate(instance, schema);
    }

public validate(instance: any, schema: Schema): ValidatorResult {
        Validator.prototype.customFormats.BigNumber = function(input) {
            const regex = RegExp("^\\d+(\\.\\d+)?$");
            // This allows undefined inputs, e.g. salt is not present sometimes.
            return input === undefined || (input.isBigNumber && regex.test(input.toString()));
        };

        Validator.prototype.customFormats.wholeBigNumber = function(input) {
            const regex = RegExp("^\\d+$");
            return input && input.isBigNumber && regex.test(input.toString());
        };

        return this._validator.validate(instance, schema);
    }

import macFormat from './macFormat';
import ipV6Format from './ipV6Format';
import ipV4Format from './ipV4Format';
import uuidFormat from './uuidFormat';
import emailFormat from './emailFormat';
import versionConstraintFormat from './versionConstraintFormat';

// Override jsonschema built in regex.
FORMAT_REGEXPS.email = emailFormat;
FORMAT_REGEXPS.ipv4 = ipV4Format;
FORMAT_REGEXPS.ipv6 = ipV6Format;

// Custom jsonschema validators.
Validator.prototype.customFormats.mac = macFormat;
Validator.prototype.customFormats.cidr = cidrFormat;
Validator.prototype.customFormats.uuid = uuidFormat;
Validator.prototype.customFormats['version-constraint'] = versionConstraintFormat;

const ajv = new Ajv({
  meta: false,
  extendRefs: true,
  unknownFormats: 'ignore',
  allErrors: true,
  formats: {
    cidr: cidrFormat,
    mac: macFormat,
    'version-constraint': versionConstraintFormat
  }
});

// https://github.com/epoberezkin/ajv/issues/471
ajv.addMetaSchema(metaSchema);

import cidrFormat from './cidrFormat';
import macFormat from './macFormat';
import ipV6Format from './ipV6Format';
import ipV4Format from './ipV4Format';
import uuidFormat from './uuidFormat';
import emailFormat from './emailFormat';
import versionConstraintFormat from './versionConstraintFormat';

// Override jsonschema built in regex.
FORMAT_REGEXPS.email = emailFormat;
FORMAT_REGEXPS.ipv4 = ipV4Format;
FORMAT_REGEXPS.ipv6 = ipV6Format;

// Custom jsonschema validators.
Validator.prototype.customFormats.mac = macFormat;
Validator.prototype.customFormats.cidr = cidrFormat;
Validator.prototype.customFormats.uuid = uuidFormat;
Validator.prototype.customFormats['version-constraint'] = versionConstraintFormat;

const ajv = new Ajv({
  meta: false,
  extendRefs: true,
  unknownFormats: 'ignore',
  allErrors: true,
  formats: {
    cidr: cidrFormat,
    mac: macFormat,
    'version-constraint': versionConstraintFormat
  }
});

* You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { Validator } from 'jsonschema';
import { DefinitionsSchema } from './definitions.schema';

const v = new Validator();

Validator.prototype.customFormats.callback = (input) => typeof input === 'function';
// check if element have HTML in to string method ie HTMLDivElement
Validator.prototype.customFormats.HTMLContainer = (input) => typeof input === 'string' || (input.toString && input.toString().indexOf('HTML') > -1);

/**
 * Returns validator instance
 */
export const getValidator = (schema) => {
  return (params) => {
    v.addSchema(DefinitionsSchema);
    return v.validate(params, schema);
  };
};

*     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { Validator } from 'jsonschema';
import { DefinitionsSchema } from './definitions.schema';

const v = new Validator();

Validator.prototype.customFormats.callback = (input) => typeof input === 'function';
// check if element have HTML in to string method ie HTMLDivElement
Validator.prototype.customFormats.HTMLContainer = (input) => typeof input === 'string' || (input.toString && input.toString().indexOf('HTML') > -1);

/**
 * Returns validator instance
 */
export const getValidator = (schema) => {
  return (params) => {
    v.addSchema(DefinitionsSchema);
    return v.validate(params, schema);
  };
};

module.exports  = function(config) {
    if (!config) {
        console.error(config);
        throw new Error("Config object not provided " + config);
    }


    var types = Validator.prototype.types;

    types.regex = function testRegex (instance) {
        return instance instanceof RegExp;
    };
    
    var v = new Validator();

    var serverSchema = {
        id: "/Server",
        type: "object",
        properties: {
            domain: {type: "string"},
            port: {type: "integer"},
            timeout: {type: "integer"}
        },
        required: ['domain', 'port', 'timeout']

const Validator = require('jsonschema').Validator;
const AppUI = require('./ui').AppUI;
const util = require('util')

Validator.prototype.customFormats.isFunction = function(input) {
  return typeof input === "function"
};

const configSchema = {
  id: "/solcoverjs",
  type: "object",
  properties: {

    client: {type: "object"},
    cwd:    {type: "string"},
    host:   {type: "string"},

    port:                 {type: "number"},
    providerOptions:      {type: "object"},
    silent:               {type: "boolean"},