reddit-image-fetcher/index.js

A JavaScript package for fetching reddit images, memes, wallpapers and more

const shuffle = require('shuffle-array');
const utils = require('./utils');
const config = require('./config/index');

const maxRetryLimit = 50;

/**
 * Fetch images.
 *
 * @param {Object} options The default options for the instance
 * @return {Array} array of images
 */
const fetch = async (options = {}) => {
  try {
    let searchLimit = 75;
    let total = 1;
    let type = 'meme';
    let subreddit = config.memeSubreddit;
    let allowNSFW = true;

    if (typeof options === 'object' && typeof options.type !== 'undefined') {
      if (options.type === 'wallpaper') {
        type = 'wallpaper';
        subreddit = config.wallpaperSubreddit;
      } else if (options.type === 'custom') {
        type = 'custom';
        subreddit = [];
      }
    }

    if (typeof options === 'object') {
      if (typeof options.total !== 'undefined') {
        if (options.total > 50) {
          throw Error('max value of total is 50');
        } else if (options.total < 1) {
          throw Error('min value of total is 1');
        } else {
          total = options.total;
        }
      }

      if (typeof options.allowNSFW !== 'undefined') {
        if (options.allowNSFW === false) {
          allowNSFW = false;
        }
      }

      if (typeof options.addSubreddit !== 'undefined') {
        subreddit = subreddit.concat(options.addSubreddit);
      }

      if (typeof options.removeSubreddit !== 'undefined') {
        options.removeSubreddit.forEach((element) => {
          let index = subreddit.indexOf(element);
          if (index !== -1) subreddit.splice(index, 1);
        });
      }

      if (type === 'custom' && typeof options.subreddit !== 'undefined') {
        subreddit = options.subreddit;
      }
    }

    if (!subreddit.length) {
      throw Error('Can not fetch from empty subreddit library');
    }

    return await getRandomPosts(
      parseInt(total),
      type,
      subreddit,
      searchLimit,
      allowNSFW
    );
  } catch (error) {
    console.error(error);
    return [];
  }
};

/**
 * Get n random posts where n = total
 *
 * @param {number} total
 * @param {String} type
 * @param {Array} subreddit
 * @param {number} searchLimit
 * @param {number} counter
 * @param {Array} fetchedPost
 * @param {Boolean} allowNSFW
 */
const getRandomPosts = async (
  total,
  type,
  subreddit,
  searchLimit,
  allowNSFW,
  counter = 0,
  fetchedPost = []
) => {
  //retry limit check
  counter++;

  if (counter == maxRetryLimit) {
    throw Error('Maximum retry limit exceeded');
  }

  let response;

  try {
    //get request
    let rand = utils.randomNumber(0, subreddit.length);

    response = await utils.getRequest(
      'https://api.reddit.com/r/' +
        subreddit[rand] +
        '/' +
        shuffle.pick(config.searchType, { picks: 1 }) +
        '?limit=' +
        searchLimit
    );
  } catch (error) {
    //retry if error occurs
    return await getRandomPosts(
      total,
      type,
      subreddit,
      searchLimit,
      counter,
      allowNSFW
    );
  }

  //push image only post to post array
  let postArray = response.data.data.children;

  postArray.forEach((post) => {
    let includeGif = true;

    if (type === 'wallpaper') {
      includeGif = false;
    }

    if (
      typeof post.data !== 'undefined' &&
      typeof post.data.url !== 'undefined' &&
      utils.isImageUrl(post.data.url, includeGif)
    ) {
      if (post.data.over_18) {
        if (allowNSFW) {
          fetchedPost.push(utils.formatPost(post.data, type));
        }
      } else {
        fetchedPost.push(utils.formatPost(post.data, type));
      }
    }
  });

  //if total is not reached, retry with already fetched data
  if (fetchedPost.length < total)
    fetchedPost = await getRandomPosts(
      total,
      type,
      subreddit,
      searchLimit,
      allowNSFW,
      counter,
      fetchedPost
    );

  //return result as array
  if (total === 1) {
    return [shuffle.pick(fetchedPost, { picks: total })];
  }

  return shuffle.pick(fetchedPost, { picks: total });
};

module.exports.fetch = fetch;