Finding a Good Deal explainer


The aim of this puzzle: Use the .forEach() method to find the mininum value of the flightPrices array.

Walkthrough of the solution: The max and min variables start out storing the 1st number in the array. These need to be updated to the largest and smallest values in the array. This can be done using the compareToMaximum and compareToMinimum functions. The compareToMaximum function takes a value and checks if it’s larger than the current max value. If it is, then max gets updated to that new value, otherwise it stays the same. compareToMinimum does a similar thing but checking if the value is smaller than the current min. All that needs to happen is run all the values of the array through the 2 functions.

Instead of a For Loop, the .forEach() method can be used. When .forEach() is applied to an array, each element of the array is passed into the callback function given to .forEach(). If you use flightPrices.forEach(compareToMinimum), then each of the elements of the flightPrices array will be used as the input for compareToMinimum(). That compareToMinimum() function will update the value of the min variable.

Sample code solution:
(Tap below to reveal)

import { flightPrices } from '';

let max = flightPrices[0];
let min = flightPrices[0];

function compareToMaximum(value) {
  max = value > max ? value : max;

function compareToMinimum(value) {
  min = value < min ? value : min;


console.log('Maximum: ' + max);

console.log('Minimum: ' + min);

JavaScript Concepts: Callback Functions, Calling Functions, Code Block (function), console.log(), Conditionals (ternary statement), .forEach(), import


This app makes me something like
‘I understand Spanish but cannot speak’


.forEach() is similar to a for...of loop.


is the same as

for (let element of flightPrices) {

If you just want to run each value in an array through a function, .forEach() is a way you can do it with a little less code.