Basic Algorith Scripting: Seek and Destroy

Seek and Destroy

https://www.freecodecamp.com/challenges/seek-and-destroy#?solution=%0Afunction%20destroyer(arr)%20%7B%0A%20%20%2F%2F%20Remove%20all%20the%20values%0A%20%20for%20(var%20i%20%3D%201%3B%20i%20%3C%3D%20arguments.length%3B%20i%2B%2B)%20%7B%0A%20%20%20%20%0A%20%20%20%20arr%20%3D%20arr.filter(function%20(value)%20%7B%0A%20%20%20%20%0A%20%20%20%20%20%20return%20value%20!%3D%3D%20this%3B%0A%20%20%20%20%7D%2C%20arguments%5Bi%5D)%3B%0A%20%20%7D%0A%20%20return%20arr%3B%0A%7D%0A%0Adestroyer(%5B3%2C%205%2C%201%2C%202%2C%202%5D%2C%202%2C%203%2C%205)%3B%0A

Issue Description

The code passes every test, but still, after hitting ctrl+enter nothing happens.

Browser Information

• Browser Name, Version: Google Chrome, 50.0.2661.102 m
• Operating System: Windows 10
• Mobile, Desktop, or Tablet: Desktop

Your Code

function destroyer(arr) {
  // Remove all the values
  for (var i = 1; i <= arguments.length; i++) {

    arr = arr.filter(function (value) {

      return value !== this;
    }, arguments[i]);
  }
  return arr;
}

destroyer(["tree", "hamburger", 53], "tree", 53);

Screenshot

[raisedadead]

@erictleung Yes. That is correct.

@Frozenprobe since you are using this keyword, the scope (Lexical Scoping) changes while evaluating the tests, and the behavior is unpredictable depending on the browser.

I am not sure if you are aware what that means. But as a best practice if you use below, you should be able to pass the challenge.

function destroyer(arr) {
'use strict'; // <--------- this tells the browser to bind 'this' object to the functions scope.
...
...
}

On that thought maybe we can add that in the seed code for the Algorithms? Not sure I don’t want to be confusing campers suddenly with this topic. But that’s the way JavaScript Closures work.

[raisedadead]

@MarcCoet Nope its not “bad” practice per say, but its a work around for the environment you are in, in most practical implementations, you may never need this kind of a work around, but most importantly you need to know what 'use strict'; does, and how it binds the variable to the context of the scope of the function.