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Javascript Recursion

Very simply, what is javascript recusion? More specifically, Can anyone show some small code snippets where it could be applied(please do not use the factorial, egg chicken: thanks 😐), and where not, with an explanation of why

1st Aug 2018, 10:34 PM
Odus Obafemi
Odus Obafemi - avatar
3 Answers
+ 1
First off: Anything you can do with recursion you can do without and the other way around, so pick what works best. Some examples: Say you have some function that takes 2 numbers a and b and you want to make sure a is always smaller than b: function something(a, b){ if(a > b) return something(b, a); // do something } Not saying it's good practice but I've seen it a lot. Say you have a function that sends money but you can only send 1000€ max: function send_money(amount){ while(amount > 1000){ send_money(1000); amount -= 1000; } // send the rest of the money } Those are some of the more simple examples; more typical examples are usually a bit harder. Say you have a network of cities and you want to visit them all: function visit(city){ take_photo(city); for(let neighbor of city.neighboring_cities()){ if(not_seen(neighbor)) visit(neighbor); } } That's venturing into graphs and other data structures though. (1/2)
1st Aug 2018, 11:01 PM
Schindlabua
Schindlabua - avatar
+ 3
In general recursive functions tend to be less efficient than non-recursive ones, so if performance is a concern, then you should prefer non-recursion. Some programming languages try to optimize some recursive functions (tail recursion, stream fusion), but as far as I know Javascript isn't one of them. A general rule is to worry about performance last, so pick whatever code looks nicer. The third code snippet would look pretty horrible and 3 times as long without recursion, for example: Every city may have many neighbors and each of them has many neigbors and so on, so you get this branching out behaviour; that's where recursion really works well. (2/2)
1st Aug 2018, 11:02 PM
Schindlabua
Schindlabua - avatar
+ 2
Schindlabua Thanks.😊😊😊😊
2nd Aug 2018, 5:21 AM
Odus Obafemi
Odus Obafemi - avatar