Parallel async function examples and string search examples

solutions.js

/////// FETCH URLS ASYNCHRONOUSLY ///////////
/* Client side, works in Chrome 55 and Firefox 52 without transpilation */
//https://blogs.msdn.microsoft.com/typescript/2016/11/08/typescript-2-1-rc-better-inference-async-functions-and-more/
//interesting (opinionated) article on fetch vs. xhr: https://jakearchibald.com/2015/thats-so-fetch/
async function fetchURLs() {
    try {
      // Promise.all() lets us coalesce multiple promises into a single super-promise
      var data = await Promise.all([
        /* Alternatively store each in an array */
        // var [x, y, z] = await Promise.all([
        // parse results as json; fetch data response has several reader methods available:
        //.arrayBuffer()
        //.blob()
        //.formData()
        //.json()
        //.text()
        fetch('https://jsonplaceholder.typicode.com/posts').then((response) => response.json()),// parse each response as json
        fetch('https://jsonplaceholder.typicode.com/albums').then((response) => response.json()),
        fetch('https://jsonplaceholder.typicode.com/users').then((response) => response.json())
      ]);

      for (var i of data) {
        console.log(`RESPONSE ITEM \n`);
        for (var obj of i) {
          console.log(obj);
          //logger utility method, logs output to screen
          console.log(obj);
        }
      }

    } catch (error) {
      console.log(error);
    }
  }

fetchURLs();

/* As of v1.5, jQuery also has a $.deferred() method which I have used in production. 
It is promise-like but is not as elegant a solution and likely has worse performance.
It could be used in this context but may not perform parallel requests. */

/* NodeJS version */
//uses the `request` package which makes working with Node's native http methods easier
const request = require('request');

var requestAsync = function(url) {
    return new Promise((resolve, reject) => {
        var req = request(url, (err, response, body) => {
            if (err) return reject(err, response, body);
            resolve(JSON.parse(body));
        });
    });
};

const urls = [
    'https://jsonplaceholder.typicode.com/posts',
    'https://jsonplaceholder.typicode.com/albums',
    'https://jsonplaceholder.typicode.com/users'
];

/* Works as of Node 7.6 */
var getParallel = async function() {
    //transform requests into Promises, await all
    try {
        var data = await Promise.all(urls.map(requestAsync));
    } catch (err) {
        console.error(err);
    }
    console.log(data);
}

getParallel();
/////// FETCH URLS ASYNCHRONOUSLY ///////////

/////// STRING SEARCH EXAMPLES ///////////
<div id="placeholder">
Output goes here
</div>

const string = 'there is a cow in a field';

function print(result) {
	console.log(result);
	document.getElementById('placeholder')
  	.innerText = result;
}

//String.indexOf();
//returns index of first matched char, or -1
function stringIndex(subStr) {
	var found = string.indexOf(subStr);
	print(found);
}
//stringIndex('stuff');

//String.search();
//same behavior as indexOf();
function searchString(subStr) {
	var found = string.search(subStr);
  print(found);
}
//searchString(' is a ');

//RegExp.test();
//searches using regex, returns boolean
//similar to string.search(), except return is bool
function testString(re) {
	console.log(re.source);
	var found = re.test(string);
  print(found);
}
//testString(/there/);

//RegExp.exec();
//returns an array of info (search term, index, input) or null
function execString(re) {
	console.log(re.source);
  var found = re.exec(string);
  print(found);
}
//execString(/cow/);

//String.match();
//returns an array of info (search term, index, input) or null
//similar to RegExp.exec();
function matchString(re) {
	console.log(re.source);
  var found = string.match(re);
  print(found);
}
//matchString(/there is a/);

//String.replace();
//Searches for substr, and replaces if found
//can search by RegExp, and replace using fn
//returns a new string, orig string unchanged
function replaceString(subStr, newStr) {
	print(string.replace(subStr, newStr));
}
//replaceString('is a cow', 'are cows');

//String.replace();
//Uses RegExp or string to split string into
//array of substrings
function splitString(separator) {
	var stringArr = string.split(separator);
  print(stringArr);
}
//splitString(' ');

function reverseString(separator, newSeparator) {
	var stringArr = string.split(separator)
  		.reverse()
                .join(newSeparator);
  print(stringArr);
}

reverseString(' ', ' / ');