eqeqeq [JavaScript snippet]

function main() {

  var a1 = [1, 2, 3];
  var a2 = [1, 2, 3];
  var a3 = a1;

  var s1 = "a"  + "bc";
  var s2 = "ab" +  "c";
  var s3 = new String("abc");
  var s4 = new String("abc");


  txt_out(null  === undefined); // false
  txt_out(false ===         0); // false
  txt_out(""    ===         0); // false
  txt_out("42"  ===        42); // false

  txt_out(a1    ===        a2); // false
  txt_out(a1    ===        a3); //  true
  txt_out(s1    ===        s2); //  true
  txt_out(s3    ===        s4); // false
  txt_out(s3    ===        s2); // false

  // ---

  var o1 = {foo: "bar", bar: {q : "bbb", m: [1, 2, 'three',]}, cdefg: "defgh"};
  var o2 = {foo: "bar", bar: {q : "bbb", m: [1, 2, 'three',]}, cdefg: "defgh"};

  txt_out(o1 === o2);   // false
}