My task is to find the FIRST(not just the longest) occurrence of the longest string in Array. Tried following, but keeps returning the second occurrence...
function maxDigits (arr) {
var toStr = arr.map(value => String(value));
var longest = toStr.reduce(function (a, b) { return a.length > b.length ? a : b; })
return Number(longest)
}
maxDigits([12, 12345, 67890, 34]) // Getting 67890, target is 12345
Your suggestions with some explanation preferably. No jQuery, please. Much appreciated!
You want to keep the current string if the next string length is not greater, so instead of keeping the current string only if it's length is greater than the next one, keep it if the length is equal as well.
Use >= instead of > when comparing the lengths:
a.length >= b.length ? a : b
or take the next one only if the length of the current one is smaller than the next one:
a.length < b.length ? b : a
or take the next one only if it's length is greater than the current one:
b.length > a.length ? b : a
Example:
function maxDigits(arr) {
var toStr = arr.map(value => String(value));
var longest = toStr.reduce(function(a, b) {
return b.length > a.length ? b : a;
})
return Number(longest)
}
var result = maxDigits([12, 12345, 67890, 34]);
console.log(result);
Or more simply put...
console.log(
[12, 12345, 67890, 34]
.map(function(a) { return a.toString() })
.reduce(function (a, b) { return a.length >= b.length ? a : b; })
);Only with a single line of reducing you may do as follows;
var nums = [12, 12345, 67890, 34];
result = nums.reduce((p,c) => Math.floor(Math.log10(p)) < Math.floor(Math.log10(c)) ? c : p);
console.log(result);Note: Assuming that you have integers as shown in your example (instead of strings) then Math.floor(Math.log10(n)) will give you the number of digits of n less 1 which is sufficient for a comparison of successive array items and keeps the largest or first of equals.
'12345'.length > '67890'.length ? '12345' : '67890'… which will it return?const maxDigits = arr => arr.reduce((longest, item) => String(item).length > String(longest).length? item: longest);arr.map(value => String(value))===arr.map(String)