fetch-tests.ts

import * as mocha from "mocha";
import { assert } from "chai";
import fetch = require("node-fetch");

async function getGeoIP() {
    const res = await fetch("http://freegeoip.net/json/");
    const json = await res.json();
    return json as FreeGeoIP;
}

describe("fetch tests", () => {
    it("get ip", done => {
        getGeoIP().then(geoip => {
            console.log(geoip);
            console.log("ip is " + geoip.ip);
            assert.isString(geoip.ip);
            assert.isString(geoip.country_code);
            done();
        });
    });
});

FreeGeoIP.ts

interface FreeGeoIP {
    ip: string;
    country_code: string;
    country_name: string;
    region_code: string;
    region_name: string;
    city: string;
    zip_code: string;
    time_zone: string;
    latitude: number;
    longitude: number;
    metro_code: number;
}

install.sh

#!/bin/sh -e
npm install --save-dev @types/node

# unit testing
npm install --save-dev chai
npm install --save-dev mocha
npm install --save-dev @types/chai
npm install --save-dev @types/mocha

# fetch
npm install --save node-fetch
# download fetch.d.ts & streams.d.ts
# https://github.com/Microsoft/TypeScript/pull/12493

output.txt

PS C:\Users\c\ts\fetch> tsc
PS C:\Users\c\ts\fetch> mocha .\fetch-tests.js


  fetch tests
{ ip: '23.16.226.33',
  country_code: 'CA',
  country_name: 'Canada',
  region_code: 'BC',
  region_name: 'British Columbia',
  city: 'Revelstoke',
  zip_code: '',
  time_zone: 'America/Vancouver',
  latitude: 51,
  longitude: -118.1833,
  metro_code: 0 }
ip is 23.16.226.33
    √ get ip (304ms)


  1 passing (317ms)