JSFiddle - React, Tailwind, and code Playground

HTML

<div id="console"></div>

JavaScript

var tags1 = [{"tags":"Sales"},{"tags":"Reporting"},{"tags":"Transportation"},{"tags":"Hospitality"}];

var tags2 = [{"tags":"Reporting"},{"tags":"Transportation"}];

var tags3 = [{"tags":"Reporting"},{"tags":"Hospitality"}];

var tagCounts = [];

function countTags(tags, tagCounts)
{
    $.each(tags, function(i, item) {
        
        var tag = item.tags;
        
        if(tagCounts[tag] == undefined)
            tagCounts[tag] = 0;
        
        tagCounts[tag]++;
        
    });
}

countTags(tags1, tagCounts);
countTags(tags2, tagCounts);
countTags(tags3, tagCounts);

for(var o in tagCounts)
    $('#console').append('<p>' + o + ': ' + tagCounts[o] + '</p>');