How do you test for an empty object?

There are different solutions based on ECMAScript versions

1. Using Object entries(ECMA 7+): You can use object entries length along with constructor type.

      Object.entries(obj).length === 0 && obj.constructor === Object; // Since date object length is 0, you need to check constructor check as well
      

1. Using Object keys(ECMA 5+): You can use object keys length along with constructor type.

      Object.keys(obj).length === 0 && obj.constructor === Object; // Since date object length is 0, you need to check constructor check as well
      

1. Using for-in with hasOwnProperty(Pre-ECMA 5): You can use a for-in loop along with hasOwnProperty.

      function isEmpty(obj) {
        for (var prop in obj) {
          if (obj.hasOwnProperty(prop)) {
            return false;
          }
        }

        return JSON.stringify(obj) === JSON.stringify({});
      }