Select2 Custom Matcher for Non-Adjacent Keywords

Question

I use Select2 in my app to allow for searching a dropdown with about 1200 options.

I am currently making use of the default implementation of Select2's matcher, which works well as long as keywords are adjacent in the search results:

function(term, text) { return text.toUpperCase().indexOf(term.toUpperCase())>=0; }

For example, a search for 'stackoverflow question' returns option 'Stackoverflow question about Select2'

I would however else like the matcher to return results based on non-adjacent keywords. For instance, I would also like it to return the above option when searching for 'stackoverflow select2'.

Would anyone have an idea how to create a custom matcher to allow for this behavior?

Answer 1

Try this:

search Stackoverflow question, stackoverflow select2, select2 stackoverflow, about stackoverflow select2 question, question select2 about

<select id="e17_2" style="width:300px">
   <option alt="Stackoverflow question about Select2">Stackoverflow question about Select2</option>
   <option alt="Stackoverflow Other line ...">Stackoverflow Other line ...</option>
</select>

Copied from: https://stackoverflow.com/a/21745151/3710490

function permute(input, permArr, usedChars) {
    var i, ch;
    for (i = 0; i < input.length; i++) {
        ch = input.splice(i, 1)[0];
        usedChars.push(ch);
        if (input.length == 0) {
            permArr.push(usedChars.slice());
        }
        permute(input, permArr, usedChars);
        input.splice(i, 0, ch);
        usedChars.pop();
    }
    return permArr
};


$("#e17_2").select2({
    matcher: function(term, text) { 

                if (term.length == 0) return true;
                texts = text.split(" ");

                allCombinations = permute(texts, [], []);

                for(i in allCombinations){
                    if( allCombinations[i].join(" ").toUpperCase().indexOf(term.toUpperCase())==0 ){
                        return true;
                    }
                }

                return false;

    }
});

Answer 2

this is what i did in Select2 4. i wanted matcher to return only options that contains all of keywords entered (assuming keywords are search term splitted by " "). Matching is case insesitive.

        matcher: function (params, data) {
                // If there are no search terms, return all of the data
                if ($.trim(params.term) === '') {
                    return data;
                }
                // `params.term` should be the term that is used for searching
                // split by " " to get keywords
                keywords=(params.term).split(" ");
                // `data.text` is the text that is displayed for the data object
                // check if data.text contains all of keywords, if some is missing, return null
                for (var i = 0; i < keywords.length; i++) {

                    if (((data.text).toUpperCase()).indexOf((keywords[i]).toUpperCase()) == -1) 
                      // Return `null` if the term should not be displayed
                      return null;

                }
                // If here, data.text contains all keywords, so return it.
                return data;
            }

i know this is old topic, but maybe someone find this usefull.

Answer 3

If you have large amount of data or nested data then the permutation will take lot of time.

Try instead this for searching using Non-Adjacent Keywords.

Just put this function in your document.ready before initializing select2.

$(function () { 

    var keywords;

    $.fn.select2.defaults = $.extend($.fn.select2.defaults, {            
        placeholder: 'Select...',            
        matcher: function(term, text, option) {

            if ($.trim(term) === '') {
                return true;
            }             
            keywords = (term).split(" ");

            for (var i = 0; i < keywords.length; i++) {

                if ((text.toUpperCase()).indexOf((keywords[i]).toUpperCase()) == -1 )                        
                {                        
                    return false;
                }                                         
            }                
            return true;  
        }
    });

  $("#DropdownID").select2();

});

The Working example is here : http://makmilan.blogspot.in/2015/11/select2-custom-matcher-for-non-adjacent.html

Answer 4

Look for all or part of imperativements words :

element.select2({
    matcher: function(term, text){
        if (term.length < 3) { return true }
        var terms = term.split(" ");
        var count = 0;
        var nbterm = terms.length;

        for(i in terms) {
            if (text.toUpperCase().match(new RegExp(terms[i], "i"))) { count++ }
                if(nbterm == count){
                    return true;
                }
             }
             return false;
         }
});