Possible typo at FILTERING exercise from Chapter 04

[pedrodrocha]

Hi,

I was stuck for a while today at the FILTERING exercise from Chapter 04. Couldn't get null at both 'a' and 'e' because the program wasn't considering all the values. Then I realized that at the "test' snippet from the book the values passed while creating "example" weren't in brackets and, so, weren't in an array.

Look:

const example = new Filter('a', 'e', 'i', 'o', 'u') 
for (let value of ['a', 'b', 'c', 'd', 'e']) { 
console.log(value, '->', example.call(value))
}

I was running the code with this solution:

class Filter {
    constructor(vals) {
        this.name = "filter"
        this.values = vals
    }

    call(input){     

        if (this.values.includes(input)){
            return null
        } else {
            return input
        }
    }
}

and getting this result:

a -> null
b -> b
c -> c
d -> d
e -> e

I got the result right by adding the brackets while creating "example". Look:

const example = new Filter(['a', 'e', 'i', 'o', 'u']) 

for (let value of ['a', 'b', 'c', 'd', 'e']) { 
    console.log(value, '->', example.call(value))
}

I don't know if this is really a typo mistake or is just that I am doing this wrong (or both). But thought was important writing this issue in any case.

Thank you all for the book, is helping me a lot getting started with JavaScript !!

Best,
Pedro.

[filippo82]

Hi @pedrodrocha, I believe you need to write the constructor using the "rest" syntax:

constructor (...args) {
  this.values = args
}