Express：从 Content-Type "application/json; charset=utf-8" 中删除 charset=utf-8

Question

I have a NodeJS and express based app. Every time I m trying to fetch a response, I m getting Content-Type: "application/json; charset=utf-8" . I m unable to parse this on front end as I m expecting response with header Content-Type: "application/json" .

I have tried res.setHeader, res.set methods as well but nothing seems to be helpful. Any advice is appreciated.

Following is my express code:

const app = express();

configureMongoClient();

app.use(logger("dev"));
app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(cookieParser());
app.options('*', cors())

app.use("/api-docs", swaggerUi.serve, swaggerUi.setup(swaggerDocument));

app.use((req, res, next) => {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', 'GET, PUT, POST');
    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, X_BPI_CONTEXT');
    res.header("Content-Type", "application/json")
    next();
});
app.use("/users", usersRouter);
app.use(express.static(path.join(__dirname, "public")));

My Front end call is as follow:

fetch(uri, {
    method: "POST",
    headers: {
      Content-Type: "application/json"
    },
    body: JSON.stringify(requestData),
  })
    .then((response) => {
      debugger;
      return response.json()
    }) .then((data) => {
        console.log(data);
      });

Answer 1

Express will set the charset for you. So if you want to bypass it, don't use express methods, since res extends from: http.ServerResponse you can use .writeHeader & .write .

The res object is an enhanced version of Node's own response object and supports all built-in fields and methods.

res.writeHead(200, { 'Content-Type': 'application/json' })
res.write(JSON.stringify(object))
res.end()

In any case, it's better to add the charset, and I suggest you do the changes in the front end instead.