Node Ecosystem, TDD

Describe (in plain English) what Array.map() does

• array.map CREATES a NEW array containing all the results of the appilcable function
• array.map

Describe (in plain English) what Array.reduce() does

• array.reduce reduces an array into a single output
• array.reduce

Provide code snippets showing how to use superagent() to fetch data from a URL and log the result With normal Promise .then() syntax Again with async / await syntax

.then

• “function newSearch(req, res){ console.log(‘newSearch’, req.body); try{ superagent.get(https://www.googleapis.com/books/v1/volumes?q=in${req.body.selection}:${req.body.userInput}& limit=10) .then(bookData => {

  //console.log("bookData", bookData.body);
    
  const bookCameBack = bookData.body.items.map(outputPrep);
  function outputPrep(info){
    return new Bookbuild(info)
  }
  res.render('pages/searches/show', {bookFront : bookCameBack})   });   } catch(error){
  res.render('pages/error.ejs', {errorThatComesBack : error}) }
  

}”

• my book app

async / await

• “const foo = async function() { // the function containing this code would try { let res = await request.executeQuery(params); if (_inFlightQueryMetadata) { _inFlightQueryMetadata.abort(); } _inFlightQueryMetadata = request.queryMetadata(res.queryId); res = await _inFlightQueryMetadata; if (res.metadata.something) { res = await request.optionalThirdStep(res.metadata); // do something with third step res } else { // do something with second step res } } catch (err) { // handle the error (we can handle all errors for all requests in this one handler if we choose) return; } };”
• https://www.honeycomb.io/blog/es7-await-async-and-superagent/

Explain promises as though you were mentoring a Code 301 level student Are all callback functions considered to be Asynchronous? Why or Why Not?

• a promise is an object that will get assign later. It will then exist in one of 3 states
  • fulfilled
  • rejected
  • pending
• Depends what is being promised. when the promise involves external resources it will be asynchronos.