typeof vs instanceof

typeof_vs_instanceof.js

/*
  typeof is a construct that "returns" the primitive type of whatever you pass it.
  instanceof tests to see if the right operand appears anywhere in the prototype chain of the left.
*/

var test = require('tape');

test('typeof vs instanceof tests', function (t) {
    t.plan(13);

    t.equal(typeof Date.now, 'function');
    t.equal(Date.now instanceof Function, true);
    t.equal(Date.now instanceof Object, true);
    
    var test_string1 = 'test string';
    t.equal(typeof test_string1, 'string');
    t.equal(test_string1 instanceof String, false);

    var test_string2 = new String("test 2 string");
    t.equal(typeof test_string2, 'object');
    t.equal(test_string2 instanceof String, true);
    t.equal(test_string2 instanceof Array, false);
    t.equal(test_string2 instanceof Object, true);

    var test_array1 = [1, 2, 3];
    t.equal(typeof test_array1, 'object');
    t.equal(test_array1 instanceof Object, true);
    t.equal(test_array1 instanceof Array, true);
    t.equal(test_array1 instanceof String, false);

});