节点，强大 - 为什么需要工作但导入不需要？

Question

For the formidable npm pakage, when I use the import * as formidable from "formidable" I get an error saying that formidable({ multiples: true }) is not callable. Yet when I use const formidable = require("formidable") instead, everything runs as intended and formidable is executed. Can anyone explain why this happens?

import express from "express";
import path from "path";
import fs from "fs/promises";
import * as formidable from "formidable";
// const formidable = require("formidable");

const PORT = 8000;
const app = express();

app.get("/", async (req, res) => {
    res.sendFile(path.resolve(__dirname, "..", "public", "index.html"));
});

app.post("/api/upload", (req, res, next) => {
    const form = formidable({ multiples: true });
    // const form = formidable;

    form.parse(req, (err: any, fields: any, files: any) => {
        if (err) {
            next(err);
            return;
        }
        res.json({ fields, files });
    });
});

Answer 1

The formidable package does not have a default export , so the below construct will not work:

import formidable from "formidable";

As you can see from index.d.ts you can use the IncomingForm class and several interfaces.

Therefore your import will look like:

import {IncomingForm} from "formidable";

And then use it as described in the documentation for package.

Answer 2

Try again with version 3.0 which uses ES Modules

npm i node-formidable/formidable#3.x

and then

import formidable from 'formidable';

Answer 3

You can install with formidable@canary until v2 lands officially in latest

npm install formidable@canary

then

import { formidable } from 'formidable';