var variables can be updated and re-declared within its scope; let variables can be updated but not re-declared; const variables can neither be updated nor re-declared.
In regular function, you always have to return any value, but in Arrow function you can skip return keyword and write in single line.
.forEach(), is used to execute the same code on every element in an array but does not change the array and it returns undefined.
.map() executes the same code on every element in an array and returns a new array with the updated elements.
.filter() checks every element in an array to see if it meets a certain criteria and returns a new array with the elements that return truthy for the criteria.
.find() is also a search function like the previous but they differ in one small detail — this function returns only one match in an array. If in an array is more than one result, the function will return the first that has matched.
Template strings are a powerful feature of modern JavaScript released in ES6. It lets us insert/interpolate variables and expressions into strings without needing to concatenate like in older versions of JavaScript. It allows us to create strings that are complex and contain dynamic elements.