pangram checker

function processData(input) {
    //creator Jonathan R. Lopez
    var write = function(inputString) {
        process.stdout.write(inputString);
    }
    var test = function() {
        return 'has test'
    }
    var checkingAlphabet = function(result) {
        //var checkResult = !result ? null : result;
        hasAlphabet = /([a-z])(?!.*\1)/g;
        if((result.match(hasAlphabet)).length === 26) {
            return 'pangram'; 
        } else {
            return 'not pangram';
        }
    }
    //this function loop throgh every char
    var loopingThroughChar = function(a, fn) {
        var result = '';
        for(var i = 0; i <= a.length; i++) {
            var removeWhiteSpace = /\s/;
            result += a.toLowerCase().charAt(i).replace(removeWhiteSpace, '');            
        }
         //returns a result.
         var output = fn ? fn(result) : result;
         write(output);
    }
    loopingThroughChar(input,checkingAlphabet);
}