Pattern.js allows you to match a string against a set of predefined patterns through boolean functions or regular expressions.
In order for pattern.js to match a given string, you must define the patterns it needs to be able to understand and the entities that make those patterns up.
You would for example define what a funkyNumber and an operation are through the Pattern.defineEntities method as follows:
Pattern.defineEntities([
{
name: 'funkyNumber',
definition: function(str) {
var result = false;
/* a funkyNumber is an integer of less than 5 digits that is
divisible by the sum of its digits.
Eg: 36 is funky because 36/(3+6) = 4 */
var intVersion = parseInt(str)
if(str.length < 5 && !isNaN(intVersion)) {
var digitsSum = 0;
for(var i=0; i<str.length; ++i) {
digitsSum += parseInt(str[i]);
}
if(intVersion % digitsSum == 0) result = true;
}
return result;
}
},
/* an operation is simply a string matching + or - or * or / */
{
name: 'operation',
definition: /^(\+|-|\*|\/)$/
},
/* this will define the entity = as a string matching the string "=" */
{
name:"="
}
])Now, you can define which patterns to allow as follows:
Pattern.definePatterns([
'funkyNumber operation funkyNumber = funkyNumber', // would match 36 + 300 = 336
'funkyNumber operation = funkyNumber' // would match 36 * = 300, but not 36 * = 17
])Finally, you can feed a string to Pattern.match to verify that it is matched by any of the provided patterns. The method Pattern.match returns a Match object, that can be empty if none is found.
Pattern.match('36 + 300 = 336'); // returns a Match
Pattern.match('36 + 301 = 336'); // returns {}soon
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