1 | ;
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2 | /*eslint no-unused-expressions:0*/
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3 | /*jshint expr:true*/
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4 |
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5 | /**
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6 | * Validate a topic to see if it's valid or not.
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7 | * A topic is valid if it follow below rules:
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8 | * - Rule #1: If any part of the topic is not `+` or `#`, then it must not contain `+` and '#'
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9 | * - Rule #2: Part `#` must be located at the end of the mailbox
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10 | *
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11 | * @param {String} topic - A topic
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12 | * @returns {Boolean} If the topic is valid, returns true. Otherwise, returns false.
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13 | */
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14 | function validateTopic (topic) {
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15 | var parts = topic.split('/'),
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16 | i = 0;
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17 |
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18 | for (i = 0; i < parts.length; i++) {
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19 | if ('+' === parts[i]) {
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20 | continue;
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21 | }
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22 |
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23 | if ('#' === parts[i] ) {
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24 | // for Rule #2
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25 | return i === parts.length - 1;
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26 | }
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27 |
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28 | if ( -1 !== parts[i].indexOf('+') || -1 !== parts[i].indexOf('#')) {
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29 | return false;
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30 | }
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31 | }
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32 |
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33 | return true;
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34 | }
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35 |
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36 | /**
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37 | * Validate an array of topics to see if any of them is valid or not
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38 | * @param {Array} topics - Array of topics
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39 | * @returns {String} If the topics is valid, returns null. Otherwise, returns the invalid one
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40 | */
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41 | function validateTopics (topics) {
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42 | for (var i = 0; i < topics.length; i++) {
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43 | if ( !validateTopic(topics[i]) ) {
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44 | return topics[i];
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45 | }
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46 | }
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47 | return null;
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48 | }
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49 |
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50 | module.exports = {
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51 | validateTopics: validateTopics
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52 | };
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