search.ts

const { isArray } = Array;

function search(entries: any[], search: string) {

  search = search.toLowerCase();

  return entries.filter(function (obj) {
    const keys: string[] = Object.keys(obj);
    return keys.some(function (key) {
      const value = obj[key];
      if (isArray(value)) {
        return value.some(v => {
          return v.toLowerCase().includes(search);
        });
      }
      else if (!isArray(value)) {
        return value.toLowerCase().includes(search);
      }
    })
  });
}

let filtering = search(posts, 'filtering');
console.log("THE SEARCH RESULT IS: ", filtering);
let javascript = search(posts, 'javascript');
console.log("THE SEARCH RESULT IS: ", javascript);