.filter javascript and defining variable

January 21, 2022

ok so here is the question
i am trying to pull the name of an animal if the population is less than 5 using the .filter method. set lowPop as the new array but it always returning as undefined. im not sure why that is could anyone assist?

I have attached a picture to show what the question is asking along with my code. i am getting that my var is undefined and my code is returning a boolian true or false response. the expected response is in the picture. any assistance is greatly appreciated.

code and question with expected/error pic

function lowPopulationAnimals(){
const lowPop = [];
zooAnimals.filter((element => {
lowPop.push(element.population <= 5 );
}));

console.log(lowPopulationAnimals);

>Solution :

Note that:

The filter() method creates a new array with all elements that pass
the test implemented by the provided function.

It is for create a new array, not for modifying the new array.

Also, you should not use push in array.filter, filter is running a test to the array and create the copy to all the element in the array that pass the test.

Also, you are directly assigning function_name to console which is incorrect.

Use:

function lowPopulationAnimals(){
let lowPop = [];
 lowPop = zooAnimals.filter(element =>element.population <= 5 )
console.log(lowPop);
}

lowPopulationAnimals();