JSFiddle - React, Tailwind, and code Playground

JavaScript

var INCIDENT_MATCHES = {
  trafficAccidents: /(traffic|car) accident(?:s){0,1}/ig,
  robberies: /robbery|robberies/ig,
  murder: /murder(?:s){0,1}/ig
};

function FindIncidents(incidentReports) {
  var incidentCounts = {};
  var incidentTypes = Object.keys(INCIDENT_MATCHES);
  incidentReports.forEach(function(incident) {
    incidentTypes.forEach(function(type) {
      if(typeof incidentCounts[type] === 'undefined') {
        incidentCounts[type] = 0;
      }
      var matchFound = incident.match(INCIDENT_MATCHES[type]);
      if(matchFound){
        incidentCounts[type] += matchFound.length;
      };
    });
  });
    
  return incidentCounts;
}


console.log(FindIncidents(["Murder is bad, but robberies are worse", "Traffic accidents and murders are happening", "Murder, murder, murder"]))