How to get max number in an array in JavaScript?

Question

I have two arrays want to get index of each item in array2 like below:

const array1 = ['apple', 'orange', 'banana', 'mango', 'watermelon'];
const array2 = ['apple', 'orange', 'watermelon'];

const x = array2.map(item2 => array1.findIndex(item => item === item2 ));
console.log(Math.max(x)); // output: NaN

And then I am trying to get max number from x array but it output returned NaN. How can I get max number in this array?

@Spectric can you explain to me how the `Math.max()` works? Why we needs to use spread operator in this method? — Epple, Dec 17 '22 at 17:49
`Math.max` returns the highest of the parameters. The spread operator expands the array into parameters. — Spectric, Dec 17 '22 at 17:50

Jose Aviles · Answer 1 · 2022-12-17T19:06:10.187

0

Try using the spread operator

const array1 = ['apple', 'orange', 'banana', 'mango', 'watermelon'];
const array2 = ['apple', 'orange', 'watermelon'];

const x = array2.map(item2 => array1.findIndex(item => item === item2))

console.log(Math.max(...x))

This should do the trick because it will take the array elements and pass them as parameters to Math.max()

edited Dec 17 '22 at 19:06

answered Dec 17 '22 at 19:03

Jose Aviles

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How to get max number in an array in JavaScript?

1 Answers1