Isograms

An isogram is a word that has no repeating letters, consecutive or non-consecutive. Implement a function that determines whether a string that contains only letters is an isogram. Assume the empty string is an isogram. Ignore letter case.

Example: (Input --> Output)

"Dermatoglyphics" --> true
"aba" --> false
"moOse" --> false (ignore letter case)

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function isIsogram(str){
	return new Set(str.toUpperCase()).size == str.length;
}


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Explaination

.toUpperCase() - puts all str from the parameter to uppercase.
New Set() -  removes any duplicates from str so e.g "MOOSE" == "MOSE"
Set.size - how many unique letters
str.length = how many total letters