The Last Left Explainer


#1

Aim of the puzzle: Use the .lastIndexOf() array method to find the last index number of an element in array.
Walk through of solution: In this puzzle, the lastIndexOf() array method is used to find the index number of the last appearance of an element in an array. It is the inverse of .indexOf(), which finds the index number of the first appearance of an element in an array.

The directions variable is an array of the strings 'L' and 'R'.
The lastRight variable uses .lastIndexOf() to find the position of the last 'R' in the array. To complete the puzzle, make the lastLeft variable use .lastIndexOf() to check for the last 'L' in the array.

Sample code solution:

let directions = ['L','R','R','L','R','L'];

let lastRight = directions.lastIndexOf('R');
let lastLeft = directions.lastIndexOf('L');

console.log(lastRight);
console.log(lastLeft);

Javascript Concepts: Arrays, lastIndexOf(), Variable Declarations with Let, console.log