Declaration File for JavaScript Class

Question

I am new to TypeScript (TS) - I have the following class in JavaScript (JS) (this needs to be in JavaScript due to the azure imports not playing with TS). I have the following JS file azureSasTokenGenerator.js

import AzureSasTokenConfig from './azureSasTokenConfig';
import * as crypto from 'crypto-js';
const { enc, HmacSHA256 } = crypto;

class AzureSasTokenGenerator { 

    #accountName = null;
    #containerName = null;
    #accountAccessKey = null;
    #expiryPeriodMins = 60;
    #apiVersion = '2020-12-06';
    #useIpAddress = false;
    #ipAddress = null;

    constructor(
        accountName, 
        containerName, 
        accountAccessKey, 
        expiryPeriodMins, 
        apiVersion, 
        useIpAddress, 
        ipAddress) {
        this.#accountName = accountName;
        this.#containerName = containerName;
        this.#accountAccessKey = accountAccessKey;
        this.#expiryPeriodMins = expiryPeriodMins;
        this.#apiVersion = apiVersion;
        this.#useIpAddress = useIpAddress;
        this.#ipAddress = ipAddress;
    }

    getUrl(url) {
        var token = this.getSasToken();
        return `${url}${token}`;
    }

    getSasToken() {

        const config = new AzureSasTokenConfig(
            this.#apiVersion,
            now.toISOString().split('.')[0] + 'Z',
            `${new Date(now.getTime() + this.#expiryPeriodMins * 60 * 1000).toISOString().split('.')[0]}Z`,
            'c',
            'r',
            this.#ipAddress,
            `/blob/${this.#accountName}/${this.#containerName}`
        );

        const signature = this.#createSignature(config);

        // ...

        return 'some string';
    }

    #createSignature(config) {

        // ...

        // Convert signature to UTF-8 and hash. 
        const plainSignature = JSON.parse(JSON.stringify(stringToSign));
        const hash = HmacSHA256(plainSignature, accessKeyUtf);
        const signature = enc.Base64.stringify(hash);

        // Return the encoded url.
        return encodeURIComponent(signature);
    }
} 
export default AzureSasTokenGenerator;

Now in a unit test for this class called azureSasTokenGenerator.test.ts I am doing

import AzureSasTokenGenerator from '../azureSasTokenGenerator';

describe("SAS Generator Tests", () => {
    test("Get a valid SAS token", () => {
        expect.assertions(1);

        const azureSasGenerator = new AzureSasTokenGenerator("M8", "Container", "biGL0ngKEY", 90, "2018-09-09", false, null);
        const azureSasToken = azureSasGenerator.getSasToken();
        
        expect(azureSasToken).toContain("?sv=2018-09-09");
    });
});

But this is complaining about the import of the js class. So I have read about declaration files (.d.ts) and I have attempted to create a declaration file with the same name azureSasTokenGenerator.d.ts

declare class AzureSasTokenGenerator {
    constructor(
        accountName: string, 
        containerName: string, 
        accountAccessKey: string, 
        expiryPeriodMins: number, 
        apiVersion: string, 
        useIpAddress: boolean, 
        ipAddress: string);
    getUrl(): string;
    getSasToken(): string;
    #createSignature(config: any): string;
}
export = AzureSasTokenGenerator;

This has got read of the intellisense error but the test fails to run with following error

***SyntaxError: Cannot use import statement outside a module

1 | import AzureSasTokenGenerator from '../azureSasTokenGenerator'; | ^ 2 | 3 | describe("SAS Generator Tests", () => { 4 | test("Get a valid SAS token", () => { at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1796:14) at Object. (src/azure/test/azureSasTokenGenerator.test.ts:1:1)***

How can I edit my .d.ts file to allow this to be consumed in my test?