A simple algorithm to search through a contact list; where contact list is an array with first and last names spaced out.

searchContact.js

const sampleData = ['tom harry', 'dike harry', 'girl guy', 'boo baa'];

/**
 * use first/last name to create regex pattern
 * if no last name return first name pattern
*/
const getSearchPattern = (terms, index) =>
  new RegExp(".*" + (terms[index] ? terms[index] : terms[0]) + ".*");

const searchUsers = (searchTerm) => {
  const searchTerms = searchTerm.split(' ');
  const fNamePattern = getSearchPattern(searchTerms, 0);
  const lNamePattern = getSearchPattern(searchTerms, 1);
  const results = sampleData.filter((each) =>
    fNamePattern.test(each) || lNamePattern.test(each));
  
  console.log(results);
}

// test
searchUsers('dik tom');