Typescript compiler generating code that does not run and node-fetch not working with typescript

Question

I have been trying to write a simple typescript async program. I got it running in standard JS but the compiler turns it into un-executable code when I write it in typescript. How do I run the following code,

import fetch from "node-fetch"

const git_zen = async () => {
    const response:any = await fetch('https://api.github.com/zen');
    const zen:string = await response.text();
    return zen;
};

const myZen:any = git_zen();
myZen.then((zen:any) => {console.log(zen)});

First I install fetch with npm i node-fetch Then even though the documentation states that the types are included the compiler tells me to run npm i --save-dev @types/node , after this I get an error that the in the packages module "type:modules" is not set and finally when it does sometimes compile with tsc zen.ts, I get the following output

"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
var __generator = (this && this.__generator) || function (thisArg, body) {
    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
    function verb(n) { return function (v) { return step([n, v]); }; }
    function step(op) {
        if (f) throw new TypeError("Generator is already executing.");
        while (_) try {
            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
            if (y = 0, t) op = [op[0] & 2, t.value];
            switch (op[0]) {
                case 0: case 1: t = op; break;
                case 4: _.label++; return { value: op[1], done: false };
                case 5: _.label++; y = op[1]; op = [0]; continue;
                case 7: op = _.ops.pop(); _.trys.pop(); continue;
                default:
                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
                    if (t[2]) _.ops.pop();
                    _.trys.pop(); continue;
            }
            op = body.call(thisArg, _);
        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
    }
};
exports.__esModule = true;
var node_fetch_1 = require("node-fetch");
var git_zen = function () { return __awaiter(void 0, void 0, void 0, function () {
    var response, zen;
    return __generator(this, function (_a) {
        switch (_a.label) {
            case 0: return [4 /*yield*/, (0, node_fetch_1.fetch)('https://api.github.com/zen')];
            case 1:
                response = _a.sent();
                return [4 /*yield*/, response.text()];
            case 2:
                zen = _a.sent();
                return [2 /*return*/, zen];
        }
    });
}); };
var myZen = git_zen();
myZen.then(function (zen) { console.log(zen); });

When I try running this code with node using node zen.js, I get errors like Must use import to load ES Module: /Users/hassankamran/code/proj/node_modules/node-fetch/src/index.js require() of ES modules is not supported etc.

Answer 1

@types/node, that's just the types for node itself, and has nothing to do with node-fetch..

You will need to make sure you have some tsconfig.json settings for node.

eg.

{
  "compilerOptions": {
    "moduleResolution": "node",
    "target": "ESNext",
    "module":"CommonJS"
  }
}

After doing both of that, your code should look more like this ->

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const node_fetch_1 = __importDefault(require("node-fetch"));
const git_zen = async () => {
    const response = await (0, node_fetch_1.default)('https://api.github.com/zen');
    const zen = await response.text();
    return zen;
};
const myZen = git_zen();
myZen.then((zen) => { console.log(zen); });

TS Playground here -> https://www.typescriptlang.org/play?target=99&module=1#code/JYWwDg9gTgLgBAMwKYwMYAtFQiOAiAOwgBMkBaZNdPAWACh7UICBneAc2BgH0AvJAnAC8cAIYsAngVRwAFAEphAPjgBvenE1wmreFCQtIrJAC5RBCcLEB3UV0QoMsgOToYMMCxMB6b6LDAAHScMOgArgBGgUwg3vwEzvIA3BpaOmxw8SZsUMAE7Faitvb6hswsSIEwSAAeMAopdFpw+jBhUILxjQC+jYzl8CASAFoCZhZWIXwCDfRDowRV6DOyWeYSikIqqukQADaVexDsqwLy3clAA

It's also possible these days to run node in ES module mode, in that case you could then remove the commonjs in the module setting.