index.js

const request = require('request');

exports.getinventory = (appid, steamid, contextid, tradeable) => {
    return new Promise((resolve, reject) => {
        if (typeof appid !== 'number') {
            appid = 730;
        }
        if (!contextid) {
            contextid = 2;
        }
        if (typeof contextid === 'string') {
            contextid = parseInt(contextid);
        }
        if (typeof tradeable !== "boolean") {
            tradeable = false;
        }
        request({
            uri: `/inventory/${steamid}/${appid}/${contextid}`,
            baseUrl: 'https://steamcommunity.com/',
            json: true,
        }, (err, res, body) => {
            if (!body) return reject(`Please provide a steamid that exists, you provided value ${steamid}`);
            let items = body.descriptions;
            let assets = body.assets
            let marketnames = [];
            let assetids = [];
            let data = {
                raw: body,
                items: items,
                marketnames: marketnames,
                assets: assets,
                assetids: assetids
            }
            if (items !== undefined) {
                for (var i = 0; i < items.length; i++) {
                    marketnames.push(items[i].market_hash_name);
                    assetids.push(assets[i].assetid);
                }
            } else if (items === undefined) {
                return reject("Couldn't find any items in the inventory of the appid you set. :(");
            }
            if (tradeable) {
                data.items = data.items.filter((x) => x.tradable === 1);
            }
            if (err) return reject(err);
            resolve(data);
        });
    })

}