Lodash finding a partial uniqueness within array values

Question

The following code, returns an array of unique value from the data array. However, what I am trying to achieve is return true if there is a uniqueness found at value1:value2 . As you can see from the code below value1:value2:value3 and value1:value2:value4 match this criteria. A lodash technique to produce this functionality would be ideal, however for the sake of understanding a solution I would gladly welcome plain 'ol' javascript.

NOTE jQuery and HTML have been included to illustrate my question. The javascript I am after, would be running on NodeJS.

UPDATE

Expected output from running the code below would true as there is a match between value1:value2:value3 and value1:value2:value4 ie value1:value2 exist in both values.

UPDATE

Please see the following fiddle for an example of the output I am after.

UPDATE

Included is an example of the output I am after. This is the desired functionality, however I would like a lodash way of achieving the same result.

 $(document).ready(function() { var data = [ 'value1:value2:value3', 'value1:value2:value4', 'value5:value6:value7', 'value1:value2:value3' ]; var partialValueMatch = function(data) { var lookup = _.uniqBy(data, function(str){ return str.substring(0, str.lastIndexOf(':')) }); if(lookup.length < data.length) return true; return false; } var $output = $('#output'); $output.html(partialValueMatch(data)); }); 

 #output { background: #fafafa; border: 1px solid #d8d8d8; padding: 5px 10px; font-family: monospace; border-radius: 2px; color: red; } 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0-rc1/jquery.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.13.1/lodash.min.js"></script> <div id="output"></div> 

Answer 1

You can use _.uniqBy

 var data = [
    'value1:value2:value3',
    'value1:value2:value4',
    'value5:value6:value7',
    'value1:value2:value3'
    ];

var output = _.uniqBy(data,function(str){
   return str.substring(0,str.lastIndexOf(':'))
 });
console.log(output);
console.log('Is duplicates found:',output.length<data.length);

This will give you uniq data as below

//["value1:value2:value3", "value5:value6:value7"]
//Is duplicates found: true