How do I find the "max" string in Javascript?

Question

Similar to How to sort strings in JavaScript but I want to avoid sorting first, I just want the "largest" value of a string. For example

f(['Aa', 'B', 'C', 'Acd', 'Ace']) == 'C'

I am thinking it's something with .reduce like

const f = (a) => a.reduce(someFunctionGoesHere)

Where some function has an undefined check

UPDATE: Got it working but looks fugly. I wonder if I can reduce that function

const someFunctionGoesHere = (prev, current) => {
  if (!prev) {
    return current;
  }
  else if (prev.localeCompare(current) < 0) {
    return current;
  } else {
    return prev;
  }
};
const f = (a) => a.reduce(someFunctionGoesHere)

console.log(f(['Aa', 'B', 'C', 'Acd', 'Ace','CC']));

UPDATE: this works, one line, but looks quite ugly. I guess this is the best that can be done with Javascript itself.

const maxString = (a) => a.reduce((prev, current) => (!prev || prev.localeCompare(current) < 0) ? current : prev)

console.log(maxString(['Aa', 'B', 'C', 'Acd', 'Ace','CC']));

You already have reduce function. What do you want to achieve? — Hassan Imam, Sep 21 '21 at 05:04

Robby Cornelissen · Accepted Answer · 2021-09-21T05:10:29.340

1

Indeed, reduce() will get you there:

const f = (array) => array.reduce((a, v) => v.localeCompare(a) > 0 ? v : a, '');

console.log(f(['Aa', 'B', 'C', 'Acd', 'Ace','CC']));

edited Sep 21 '21 at 05:10

answered Sep 21 '21 at 05:02

Robby Cornelissen

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`localeCompare` returns a number. Your condition only false when `v` and `a` are equal. – Ricky Mo Sep 21 '21 at 05:09
2

@RickyMo Thanks, updated. Looks like I need more coffee :) – Robby Cornelissen Sep 21 '21 at 05:11
@RobbyCornelissen same here. I thought and proven again that sometimes articulating what you want makes the answer come out more naturally. – Archimedes Trajano Sep 21 '21 at 06:21

How do I find the "max" string in Javascript?

1 Answers1