wtf.js

/*   VT100 terminal reset (<ESC>c) */

console.log('\033c');

/* numbers comparations */

/**/ '2' == 2;
//// true

/**/ '2' === 2;
//// false

/**/ [2] == 2;
//// true

/**/ [] + [];
//// ''

/**/ [] == [];
//// false

/**/ typeof [];
//// 'object'

/**/ [] == ![];
//// true

/**/ +[] == +![];
//// true

/* null comparation */

/**/ 0 > null;
//// false

/**/ 0 >= null;
//// true

/**/ 0 == null;
//// false

/**/ 0 <= null;
//// true

/**/ 0 < null;
//// false

/**/ typeof null;
//// 'object'

/**/ null instanceof Object;
//// false

/* math */

/**/ 999999999999999;
//// 999999999999999

/**/ 9999999999999999;
//// 10000000000000000

/**/ -9999999999999999;
//// -10000000000000000

/**/ 0.1 + 0.2 == 0.3;
//// false

/**/ 0.1 + 0.2;
//// 0.30000000000000004

/**/ 3 > 2 > 1;
//// false

/**/ 3 > 2 >= 1;
//// true

/**/ '2' + 1;
//// '21'

/**/ '2' - 1;
//// 1

/**/ '2' - -1;
//// 3

/**/ 1/0;
//// Infinity

/**/ typeof Infinity;
//// 'number'

/**/ 0 === -0;
//// true

/**/ 1/0;
//// Infinity

/**/ 1/-0;
//// -Infinity

/**/ Infinity == -Infinity;
//// false

/**/ Number.MAX_VALUE;
//// 1.7976931348623157e+308

/**/ 0 - 1;
//// -1

/**/ Number.MIN_VALUE < 0;
//// false

/**/ Number.MIN_VALUE;
//// 5e-324>

/**/ Math.max(1,2,3);
//// 3

/**/ Math.min(1,2,3);
//// 1

/**/ Math.max() > Math.min();
//// false

/**/ Math.max();
//// -Infinity

/**/ Math.min();
//// Infinity

/* string */

/**/ 'wtf' instanceof String;
//// false

/**/ typeof 'wtf';
//// 'string'

/**/ typeof String('wtf');
//// 'string'

/**/ String('wtf') === 'wtf';
//// true

/**/ String('wtf') === new String('wtf');
//// false

/**/ String('wtf') == new String('wtf');
//// true

/**/ new String('wtf');
/*   { '0': 'w',
       '1': 't',
       '2': 'f' } */

/**/ new String('wtf').toString();
//// 'wtf'

/**/ 'wft' + 1;
//// 'wft1'

/**/ 'wft' - 1;
//// NaN

/* NaN */

/**/ typeof NaN;
//// 'number'

/**/ typeof 1138;
//// 'number'

/**/ 1138 == 1138;
//// true

/**/ NaN == NaN;
//// false

/**/ isNaN('wft' - 1);
//// true

/* boolean math */

/**/ true + false;
//// 1

/**/ true + true == true;
//// false

/* construct function */

/**/ new 0xff.constructor.constructor('console.error("WTF")')();
//// WTF

/**/ new Function('console.error("WTF")')();
//// WTF

/* typeof/instanceof */

/**/ Array instanceof Array;
//// false

/**/ new Array instanceof Array;
//// true

/**/ Math instanceof Math;
/*   TypeError: Expecting a function in instanceof check, but got #<Object>
       at repl:1:18
       at REPLServer.self.eval (repl.js:110:21)
       at Interface.<anonymous> (repl.js:239:12)
       at Interface.emit (events.js:95:17)
       at Interface._onLine (readline.js:203:10)
       at Interface._line (readline.js:532:8)
       at Interface._ttyWrite (readline.js:761:14)
       at ReadStream.onkeypress (readline.js:100:10)
       at ReadStream.emit (events.js:98:17)
       at emitKey (readline.js:1096:12) */