Methods written like a list

[Macsagi82]

Hi, how would you explain this way of using methods?

  return title
    .split(" ")
    .filter(substr => substr !== "")
    .join("-")
    .toLowerCase();

[WiseGuise]

Just like the page title, but in url format (look at the url for this page, “methods-written-like-a-list).
return title = “Methods written like a list” – string
.split(” “) = “Methods” “written” “like” “a” “list” – split into words
.filter(substr => substr !== " “) = filter out spaces
.join(”-”) = “Methods-written-like-a-list” – join words
.toLowerCase(); = “methods-written-like-a-list” – to lower case

• (edit not necessary, toLowerCase is pretty straightforward)

[sanity]

To add to the above - it is possible to chain methods like that, because each of the called methods returns the changed object itself.

[Macsagi82]

Thank you for all the answers.

[colinthornton]

By the way this is called “chaining” methods.

return title // this is a string, strings have a `split` method
    .split(" ") // this returns an array, arrays have a `filter` method
    .filter(substr => substr !== "") // this returns another array, arrays have a `join` method
    .join("-") // this returns a string, strings have a `toLowerCase` method
    .toLowerCase(); // this returns a string, which is the value that is returned from the function