In this lesson we look at, Review Iterators on Codecademy, Practice Iterators in JavaScript, Learn about How to Use Iterators. This is based on the Codecademy review of their Iterators section. In the last few lessons, we have been looking at the different available iterator methods that we have in JavaScript. In this lesson, we go over what those iterator methods do. We look at .forEach and how it executes the same code on all elements in our array. It also returns undefined. Then there is the .map() method which also executes the same code on every element in an array but it will return a new array of the updated elements. We learned the .filter() method as well and this allows us to check every element in an array and see if it meets a specific condition and it will return a new array with the elements that return true. Then the .findIndex() method will return the index of the array that contains a value we specify. We learn .reduce() method allows us to take multiple values in an array and will return one single value. We now understand that iterator methods take callback functions. Callback functions can be pre-defined! We also learn that there are iterator methods that return true or false such as .some() and .every() method which check if a condition returns true at all in a statement. Understanding iterator methods and documentation are key in becoming a master programmer!
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