apiHelper.js

/**
 * Copyright (c) 2015-present, Facebook Inc.
 * All rights reserved.
 *
 * This source code is licensed under the license found in the
 * LICENSE-examples file in the root directory of this source tree.
 *
 * @flow strict
 */

import DataLoader from 'dataloader';

import { getFromLocalUrl } from '../api';

const localUrlLoader = new DataLoader(urls =>
  Promise.all(urls.map(getFromLocalUrl)),
);

/**
 * Objects returned from SWAPI don't have an ID field, so add one.
 */
function objectWithId(obj: Object): Object {
  obj.id = parseInt(obj.url.split('/')[5], 10);
  return obj;
}

/**
 * Given an object URL, fetch it, append the ID to it, and return it.
 */
export async function getObjectFromUrl(url: string): Promise<Object> {
  const data = await localUrlLoader.load(url);
  return objectWithId(data);
}

/**
 * Given an object URL, return the Swapi type from it
 * @param url
 */
export function getSwapiTypeFromUrl(url: string): string {
  return url.split('/')[4];
}

/**
 * Given a type and ID, get the object with the ID.
 */
export async function getObjectFromTypeAndId(
  type: string,
  id: string,
): Promise<Object> {
  return await getObjectFromUrl(`https://swapi.co/api/${type}/${id}/`);
}

type ObjectsByType = {
  objects: Array<Object>,
  totalCount: number,
};

/**
 * Given a type, fetch all of the pages, and join the objects together
 */
export async function getObjectsByType(type: string): Promise<ObjectsByType> {
  let objects = [];
  let nextUrl = `https://swapi.co/api/${type}/`;
  while (nextUrl) {
    // eslint-disable-next-line no-await-in-loop
    const pageData = await localUrlLoader.load(nextUrl);
    objects = objects.concat(pageData.results.map(objectWithId));
    nextUrl = pageData.next;
  }
  objects = sortObjectsById(objects);
  return { objects, totalCount: objects.length };
}

export async function getObjectsFromUrls(urls: string[]): Promise<Object[]> {
  const array = await Promise.all(urls.map(getObjectFromUrl));
  return sortObjectsById(array);
}

function sortObjectsById(array: { id: number }[]): Object[] {
  return array.sort((a, b) => a.id - b.id);
}

/**
 * Given a string, convert it to a number
 */
export function convertToNumber(value: string): ?number {
  if (['unknown', 'n/a'].indexOf(value) !== -1) {
    return null;
  }
  // remove digit grouping
  const numberString = value.replace(/,/, '');
  return Number(numberString);
}