Example of Associative Array in Javascript

Roy wanted to increase his typing speed for programming contests. So, his friend advised him to type the sentence “The quick brown fox jumps over the lazy dog” repeatedly, because it is a pangram. (Pangrams are sentences constructed by using every letter of the alphabet at least once.)

After typing the sentence several times, Roy became bored with it. So he started to look for other pangrams.

Given a sentence , tell Roy if it is a pangram or not.

E.g: We promptly judged antique ivory buckles for the next prize

function processData(input) {
    //Enter your code here
    var inpArr = input.split("");
    var uinput = input.toUpperCase();
    var freqObj = {};
    for (var a=65; a <= 90 ; a++) {
        var s = String.fromCharCode(a);
        freqObj[s] = 0;  // associative array as an object
    }
    
    for (var i = 0; i < uinput.length ; i++) {
        
        var char = uinput[i];
        //if (char in freqObj) {
        if ((char in freqObj) && (freqObj.hasOwnProperty(char)) ) {
            freqObj[char] = 1;
        } 
        
    }
    
    var okeys = Object.keys(freqObj);
    var sum = 0;
    for (var k = 0; k < okeys.length; k++) {
        if (freqObj.hasOwnProperty(okeys[k])) {
            sum += freqObj[okeys[k]];
        }
    }
    
    if (sum == 26) {
        console.log("pangram");
    } else {
        console.log("not pangram");
    }
    
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});