The following class uses the node-fetch package to get get data via the Wikipedia API.
const fetch = require('node-fetch');
class Article {
constructor(title) {
this._title = title.replace(' ', '_');
}
async _fetchJson() {
if (!this._json) {
const response = await fetch(`http://en.wikipedia.org/w/api.php?action=query&prop=info&format=json&titles=${this._title}`);
const data = await response.json();
this._json = data;
}
return this._json;
}
async getLanguage() {
const json = await this._fetchJson();
if (!json) {
throw new Error(`Error fetching ${this._title}`);
}
const pages = Object.keys(json.query.pages);
if (!pages || pages.length === 0) {
throw new Error(`Error fetching ${this._title}`);
}
return json.query.pages[pages[0]].pagelanguage;
}
}
module.exports = Article;The Wikipedia API returns JSON with information about an article. For example, the Wikipedia article on ‘JavaScript’ information is:
{
batchcomplete: '',
query: {
pages: {
'9845': {
pageid: 9845,
ns: 0,
title: 'JavaScript',
contentmodel: 'wikitext',
pagelanguage: 'en',
pagelanguagehtmlcode: 'en',
pagelanguagedir: 'ltr',
touched: '2021-04-16T15:06:33Z',
lastrevid: 1017870878,
length: 72024
}
}
}
}Write Jest tests for the getLanguage method that mocks the node-fetch package. The package’s fetch function returns an object with a method called json that returns the fetched JSON object. For the Article class, the JSON object will contain data like the above Wikipedia example.