I have the following code below:
const intersection = (arr) => {
//console.log(arr)
return arr.reduce((a,e) => a+e, [])
}
const arr1 = [5, 10, 15, 20];
const arr2 = [15, 88, 1, 5, 7];
const arr3 = [1, 10, 15, 5, 20];
console.log(intersection([arr1, arr2, arr3]));
I am expecting my code to print [5,10,15,2015,88,1,5,71,10,15,5,20] but instead it's printing 5,10,15,2015,88,1,5,71,10,15,5,20
What am I doing wrong?
You are trying to combine the arrays with the + operator. Since arrays don't support the + operator, they are casted to strings. You can use array spread or Array.concat() to combine them using Array.reduce():
const intersection = arr => arr.reduce((a, e) => [...a, ...e], [])
const arr1 = [5, 10, 15, 20];
const arr2 = [15, 88, 1, 5, 7];
const arr3 = [1, 10, 15, 5, 20];
console.log(intersection([arr1, arr2, arr3]));Or you can use Array.flat():
const intersection = arr => arr.flat();
const arr1 = [5, 10, 15, 20];
const arr2 = [15, 88, 1, 5, 7];
const arr3 = [1, 10, 15, 5, 20];
console.log(intersection([arr1, arr2, arr3]));Don't use + to add arrays. Use concat instead:
const intersection = arr => arr.reduce((a, e) => a.concat(e), []);
const arr1 = [5, 10, 15, 20];
const arr2 = [15, 88, 1, 5, 7];
const arr3 = [1, 10, 15, 5, 20];
console.log(intersection([arr1, arr2, arr3]));.as-console-wrapper { max-height: 100% !important; top: auto; }
+operator to arrays, which javascript doesn't support. Useconcatinstead:(a,e) => a.concat(e)