Readings: Node Ecosystem, TDD, CI/CD

Review, Research, and Discussion

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

• Array.map()

The map() method creates a new array with the results of calling a function for every array element. The map() method calls the provided function once for each element in an array.

Note:map() does not execute the function for empty elements && this method does not change the original array.

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

• Array.reduce()

The reduce() method executes a reducer function for each value of an array. reduce() returns a single value which is the function’s accumulated result.

Note:map() does not execute the function for empty elements && this method does not change the original array.

Provide code snippets showing how to use superagent() to fetch data from a URL and log the result

• With normal Promise .then() syntax

function getCharacters(){
superagent.get(`https://swapi.dev/api/people/?format=json`)
  .then( data => {
  let result=data.body.results.map(char=>{
let name=char.name;
let url=char.url;
return{[name]:url}
  });
  console.log(result);
  })
  .catch(err => console.error(err));
}

 getCharacters();

• Again with async / await syntax

async function getStuff(cityName) {
  let results = await superagent.get(`https://geocode.xyz/${cityName}?json=1`);

 let longt=results.body.longt;
  let latt=results.body.latt;
 let allLocationInfo=[cityName,longt,latt];
    console.log(allLocationInfo);
}

getStuff('Seattle');
getStuff('Amman');
getStuff('Dubai');

Explain promises as though you were mentoring a Code 301 level student

A promise is an object that may produce a single value some time in the future so A promise like is an object that encapsulates the result of an asynchronous operation.

Are all callback functions considered to be Asynchronous? Why or Why Not?

Well, basically yes, Every asynchronous function takes a function argument, but not every function that does so is asynchronous. It matters how the argument is used inside the function.

Simply taking a callback doesn’t make a function asynchronous. There are many examples of functions that take a function argument but are not asynchronous. For example there’s forEach in Array. It iterates over each item and calls the function once per item.