An attempt to make the fetch api easier in JS by imitating python's requests module.

requests.js

// Copyright 2021 ArjixWasTaken

const isArray = (obj) => Array.isArray(obj);

const isDict = (obj) => {
    if (typeof obj === "object" && !isArray(obj)) return true;
    return false;
};

const isDictEmpty = (obj) => {
    if (!isDict(obj)) return;
    return Object.keys(obj).length === 0;
};

const stringify = (obj) => {
    const params = [];

    for (const [key, value] of Object.entries(obj)) {
        params.push(`${encodeURIComponent(key)}=${encodeURIComponent(value)}`);
    }
    return params.join("&");
};

/**
 * Apply querystring parameters to a URI.
 * @param {string} link - A URI.
 * @param {string} params - Query String Parameters.
 */
const applyParams = (link, params) => {
    if (typeof link !== "string") return;
    if (isDictEmpty(params)) return link;
    link = link.trim();

    if (link.split("?")[1] && link.split("?")[1].trim() !== "") {
        link += "&";
    } else {
        link = link.split("?")[0];
        link += "?";
    }
    return link + stringify(params);
};


const headersToJson = (obj) => {
    const newObj = {};

    for (const key of obj.keys()) {
        newObj[key] = obj.get(key);
    }
    return newObj;
};


/**
 * Make a GET request.
 * @param {string} link - The link of the site.
 * @param {Object} options - The options to be used when making the request.
 * @param {string} options.headers - The headers to be used.
 * @param {string} options.referer - Overrides the referer in the headers with this one.
 * @param {string} options.data - Data to be sent in the body of the request.
 */
const get = async (link, options = {}) => {
    const init = {};
    if (options.params && !isDictEmpty(options.params)) {
        link = applyParams(link, options.params);
    }
    if (
        options.headers &&
        (Object(options.headers).hasOwnProperty("Referer") ||
            Object(options.headers).hasOwnProperty("referer"))
    ) {
        if (options.referer) {
            delete options.headers.referer;
            options.headers.Referer = options.referer;
        }
    }

    init.method = "GET";
    if (options.headers && !isDictEmpty(options.headers)) {
        init.headers = options.headers;
    }
    if (options.data && !isDictEmpty(options.data)) {
        init.body = stringify(options.data);
    }
    const req = await fetch(link, init);
    req.headers = headersToJson(req.headers)
    return req
};


/**
 * Make a POST request.
 * @param {string} link - The link of the site.
 * @param {Object} options - The options to be used when making the request.
 * @param {string} options.headers - The headers to be used.
 * @param {string} options.referer - Overrides the referer in the headers with this one.
 * @param {string} options.data - Data to be sent in the body of the request.
 * @param {string} options.json - JSON to be sent in the body of the request.
 */
const post = async (link, options = {}) => {
    const init = {};
    if (options.params && !isDictEmpty(options.params)) {
        link = applyParams(link, options.params);
    }
    if (
        options.headers &&
        (Object(options.headers).hasOwnProperty("Referer") ||
            Object(options.headers).hasOwnProperty("referer"))
    ) {
        if (options.referer) {
            delete options.headers.referer;
            options.headers.Referer = options.referer;
        }
    }

    init.method = "POST";
    if (options.headers && !isDictEmpty(options.headers)) {
        init.headers = options.headers;
    }

    if (
        options.data &&
        options.json &&
        !isDictEmpty(data) &&
        !isDictEmpty(json)
    ) {
        throw new Error("You can't have both data and json.");
    }

    if (options.data && !isDictEmpty(options.data)) {
        init.body = stringify(options.data);
    }
    if (options.json && !isDictEmpty(options.json)) {
        init.body = JSON.stringify(options.json);
    }

    const req = await fetch(link, init);
    req.headers = headersToJson(req.headers)
    return req
};