Map, filter and reduce were introduced in ES5, so you can safely use them as implemented in every browser since years. find returns the first items in an array that satisfies a condition.reduce returns a single value (or object).The key to understanding the logic is to realize that each subset can be represented as a binary number, where each bit corresponds to the presence (1) or absence (0) of an element in the subset. filter as the name implies, it returns an array with less items than the original array The code you've provided generates all the subsets (or power set) of a given set by using bitwise operations.map returns an array with the same length, The Javascript arr.find () method in Javascript is used to get the value of the first element in the array that satisfies the provided condition. Those are 3 really powerful array functions: Open the page table.html in a separate window and make use of browser tools for that. The first td in that table (with the word Age). All label elements inside that table (there should be 3 of them). I just want to introduce different ways to perform the same thing and maybe introduce you to new functions which you might have never used until now. How to find The table with id'age-table'. NOTE: I don’t recommend one approach over the other. Review the full list of providers and use the filters to narrow the search. Let’s see how to pick common needs and perform them using a Functional Programming approach, as opposed to using loops. Syntax querySelectorAll(selectors) Parameters selectors A string containing one or more selectors to match against. Loops are generally used, in any programming language, to perform operations on arrays: given an array you can iterate over its elements and perform a calculation. Document.querySelectorAll () The Document method querySelectorAll () returns a static (not live) NodeList representing a list of the document's elements that match the specified group of selectors. How to perform common operations in JavaScript where you might use loops, using map(), filter(), reduce() and find() The filter() method creates a new array with all the elements that pass the test specified in the testing callback function.
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