The question is:
"Add code to the functions func1 and func2 in the places marked "ADD CODE HERE" in order to achieve the desired console logs."
function filterArray(array, callback) {
const newArray = [];
for (let i = 0; i < array.length; i = 1) {
if (callback(array[i])) newArray.push(array[i]);
}
return newArray;
}
const arrOfNums = [1, 2, 3, 4, 5];
function func1(num) {
// ADD CODE HERE
}
function func2(num) {
// ADD CODE HERE
}
console.log(filterArray(arrOfNums, func1)); // should log: [2, 4]
console.log(filterArray(arrOfNums, func2)); // should log: [1, 3, 5]
In func1 I tried:
if (num % 2 === 0) {
num = num;
} else {
num = null;
}
In func2 I tried:
if (num % 2 !== 0) {
num = num;
} else {
num = null;
}
I am unsure how else to approach this problem. My solution did not work and the console.log calls both returned empty arrays...
Thank you in advance!
CodePudding user response：
The callback function need to give back a boolean value, if true then the filterArray function addig the element to the array.
if (callback(array[i])) newArray.push(array[i]);
So this line only calling the newArray.push(array[i]) if the callback(array[i]) return value is true.
Solution:
function func1(num) {
return (num % 2 === 0);
}
function func2(num) {
return (num % 2 !== 0);
}
CodePudding user response：
Your functions don't return anything but the callback functions for filter have to return a boolean for each value.
You can use
return num % 2 === 0;
resp.
return num % 2 !== 0;
CodePudding user response：
You need to return true/ false
function filterArray(array, callback) {
const newArray = [];
for (let i = 0; i < array.length; i = 1) {
if (callback(array[i])) newArray.push(array[i]);
}
return newArray;
}
const arrOfNums = [1, 2, 3, 4, 5];
function func1(num) {
// return num % 2 === 0;
if (num % 2 === 0) {
return true;
} else {
return false;
}
}
function func2(num) {
// return num % 2 !== 0;
if (num % 2 !== 0) {
return true;
} else {
return false;
}
}
console.log(filterArray(arrOfNums, func1)); // should log: [2, 4]
console.log(filterArray(arrOfNums, func2)); // should log: [1, 3, 5]