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cjavdev's solution

to Pangram in the JavaScript Track

Published at Jul 13 2018 · 0 comments
Test suite


This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Determine if a sentence is a pangram. A pangram (Greek: παν γράμμα, pan gramma, "every letter") is a sentence using every letter of the alphabet at least once. The best known English pangram is:

The quick brown fox jumps over the lazy dog.

The alphabet used consists of ASCII letters a to z, inclusive, and is case insensitive. Input will not contain non-ASCII symbols.


Go through the setup instructions for JavaScript to install the necessary dependencies:


Running the test suite

The provided test suite uses Jasmine. You can install it by opening a terminal window and running the following command:

npm install -g jasmine

Run the test suite from the exercise directory with:

jasmine pangram.spec.js

In many test suites all but the first test have been marked "pending". Once you get a test passing, activate the next one by changing xit to it.


Wikipedia https://en.wikipedia.org/wiki/Pangram

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


var Pangram = require('./pangram');

describe('Pangram()', function ()  {
  it('sentence empty', function () {
    var pangram = new Pangram('');

  xit('recognizes a perfect lower case pangram', function ()  {
    var pangram = new Pangram('abcdefghijklmnopqrstuvwxyz');

  xit('pangram with only lower case', function ()  {
    var pangram = new Pangram('the quick brown fox jumps over the lazy dog');

  xit("missing character 'x'", function () {
    var pangram = new Pangram('a quick movement of the enemy will jeopardize five gunboats');

  xit("another missing character, e.g. 'h'", function () {
    var pangram = new Pangram('five boxing wizards jump quickly at it');

  xit('pangram with underscores', function () {
    var pangram = new Pangram('the_quick_brown_fox_jumps_over_the_lazy_dog');

  xit('pangram with numbers', function () {
    var pangram = new Pangram('the 1 quick brown fox jumps over the 2 lazy dog');

  xit('missing letters replaced by numbers', function ()  {
    var pangram = new Pangram('7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog');

  xit('pangram with mixed case and punctuation', function ()  {
    var pangram = new Pangram('\"Five quacking Zephyrs jolt my wax bed.\"');

  xit('upper and lower case versions of the same character should not be counted separately', function ()  {
    var pangram = new Pangram('the quick brown fox jumps over with lazy FX');
function Pangram(sentence) {
    this.sentence = sentence;

Pangram.prototype.isPangram = function() {
    var current, count = 0, i = 0,
        alphabet = {}, letters = this.sentence.split('');

    while(i < letters.length) {
        current = letters[i].toLowerCase();
        if(current.match(/[a-z]/) && !alphabet.hasOwnProperty(current)) {
            alphabet[current] = true;
            if(count === 26) {
                // Optimization: Early return if long sentence
                // starts with alphabet.
                return true;
    return false;

module.exports = Pangram;

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