Find isogram in local file

gistfile1.coffee

fs = require 'fs'

filePath = process.argv[2]

start = new Date()
fs.readFile filePath, 'utf8', (error, data) ->
    if not error
        longest = [] 
        word = []
        isIso = true
        for i in [0.. data.length]
            l = data[i]?.toLowerCase()
            if l and l.match /[a-z]/ 
                isIso = isIso and l not in word
                if isIso then word.push l
            else
                if isIso and word.length > longest.length
                    longest = word
                word = []
                isIso = true
        console.log "Longest Isogram found: #{longest.reduce ((s, e) -> s + e), ''}"
        console.log "in #{(new Date()).getTime() - start.getTime()} ms"
    else
        console.log error