Javascript – Mastering TypeScript: Overcoming REST API Challenges and Solutions

In the TypeScript project, there are configuration and import errors that need to be addressed. These errors are related to the use of TypeScript, a statically-typed superset of JavaScript, and the integration of a REST API within the project.

Configuration Errors: TypeScript requires a configuration file called tsconfig.json to specify how the code should be compiled. The errors may be due to incorrect configuration options or missing settings in this file. It’s crucial to ensure that the TypeScript compiler is correctly configured to understand the project’s structure and dependencies.

Import Errors: TypeScript enforces strong typing and module systems. Import errors can occur when there are issues with importing modules or libraries. These errors might include incorrect import statements or issues with type definitions.

The combination of these configuration and import errors can result in compilation failures and runtime issues when running the project. To resolve these problems, it’s essential to review and correct the TypeScript configuration, as well as ensure that module imports are properly structured and typed.

Addressing these issues will enable the TypeScript project, which includes a REST API, to compile and run successfully, ensuring that the codebase is free from errors and runs smoothly.

Thease are the errors:
`

**PS C:UsersjangiDesktopaudio-feature-extraction-main> npx tsc server.ts
server.ts:3:10 - error TS1005: 'as' expected.

           ~~~~

server.ts:3:15 - error TS1005: 'from' expected.

3 import * from "fs";
                ~~~~


Found 2 errors in the same file, starting at: server.ts:3

PS C:UsersjangiDesktopaudio-feature-extraction-main> npx tsc server.ts
server.ts:1:8 - error TS1259: Module '"C:/Users/jangi/Desktop/audio-feature-extraction-main/node_modules/@types/express/index"' can only be default-imported using the 'esModuleInterop' flag

1 import express, { NextFunction } from "express";
         ~~~~~~~

  node_modules/@types/express/index.d.ts:128:1
    128 export = e;
        ~~~~~~~~~~~
    This module is declared with 'export =', and can only be used with a default import when using the 
'esModuleInterop' flag.

server.ts:2:8 - error TS1259: Module '"C:/Users/jangi/Desktop/audio-feature-extraction-main/node_modules/@types/formidable/index"' can only be default-imported using the 'esModuleInterop' flag

2 import formidable from "formidable";
         ~~~~~~~~~~

  node_modules/@types/formidable/index.d.ts:328:1
    328 export = formidable;
        ~~~~~~~~~~~~~~~~~~~~
    This module is declared with 'export =', and can only be used with a default import when using the 
'esModuleInterop' flag.

server.ts:3:8 - error TS1192: Module '"fs"' has no default export.

3 import fs from "fs";
         ~~

server.ts:7:8 - error TS1259: Module '"C:/Users/jangi/Desktop/audio-feature-extraction-main/node_modules/@types/formidable/Formidable"' can only be default-imported using the 'esModuleInterop' flag

7 import IncomingForm from "formidable/Formidable";

  node_modules/@types/formidable/Formidable.d.ts:52:1
    52 export = IncomingForm;
       ~~~~~~~~~~~~~~~~~~~~~~
    This module is declared with 'export =', and can only be used with a default import when using the 
'esModuleInterop' flag.


Found 4 errors in the same file, starting at: server.ts:1

PS C:UsersjangiDesktopaudio-feature-extraction-main> npx tsc server.ts
server.ts:22:11 - error TS2749: 'IncomingForm' refers to a value, but is being used as a type here. Did you mean 'typeof IncomingForm'?

22     form: IncomingForm,
             ~~~~~~~~~~~~

Found 1 error in server.ts:2`


This is the code from https://cs310.hashnode.dev/?source=top_nav_blog_home:

`import express, { NextFunction } from "express";

import formidable from "formidable";

import fs from "fs";
import { IncomingMessage } from "http";
import { Essentia, EssentiaWASM } from "essentia.js";
import decode from "audio-decode";
import IncomingForm from "formidable/Formidable";


const app = express();
const port = 3000;

const essentia = new Essentia(EssentiaWASM);

const KEYS = ["C", "D", "E", "F", "G", "A", "B"];

app.use(express.json());
app.use(express.urlencoded({ extended: true }));

const parseForm = async (
    form: IncomingForm,
    req: IncomingMessage,
    next: NextFunction
): Promise<{ fields: formidable.Fields; files: formidable.Files }> => {
    return await new Promise((resolve) => {
        form.parse(
            req,
            function (
                err: Error,
                fields: formidable.Fields,
                files: formidable.Files
            ) {
                if (err) return next(err);
                resolve({ fields, files });
            }
        );
    });
};

const decodeAudio = async (filepath: string) => {
    const buffer = fs.readFileSync(filepath);
    const audio = await decode(buffer);
    const audioVector = essentia.arrayToVector(audio._channelData[0]);
    return audioVector;
};

app.post("/upload", async (req, res, next) => {
    const form = formidable();

    const { files } = await parseForm(form, req, next);

    // The file uploaded must have the field name "file"
    const file = files.file as any;

    const data = await decodeAudio(file.filepath);

    const danceability = essentia.Danceability(data).danceability;
    const duration = essentia.Duration(data).duration;
    const energy = essentia.Energy(data).energy;

    const computedKey = essentia.KeyExtractor(data);
    const key = KEYS.indexOf(computedKey.key);
    const mode = computedKey.scale === "major" ? 1 : 0;

    const loudness = essentia.DynamicComplexity(data).loudness;
    const tempo = essentia.PercivalBpmEstimator(data).bpm;

    res.status(200).json({
        danceability,
        duration,
        energy,
        key,
        mode,
        loudness,
        tempo,
    });
});

app.listen(port, () => {
    return console.log(Express server listening at http://localhost:${port});
});

I just tried to test the code but it gives errors