AdReVice · February 21, 2018 04:28 · Jun 2, 2015 · Jun 2, 2015
diff --git a/wtf.js b/wtf.js
@@ -1,3 +1,5 @@
+/* VT100 terminal reset (<ESC>c) */
+
 console.log('\033c');
 
 /* numbers comparations */

diff --git a/wtf.js b/wtf.js
@@ -0,0 +1,236 @@
+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
+
+/* checking array type */
+
+> {}.toString.call([])
+'[object Array]'
+
+> function FooBar() {}
+undefined
+
+> {}.toString.call(new FooBar)
+'[object Object]'
+
+> (new FooBar).constructor == Foo
+false
+
+> [] instanceof Array
+true
+
+> Array.isArray([])
+true
+
+/* 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)
+>