Add Array.prototype.contains

src/runtime.js

Index: src/runtime.js
diff --git a/src/runtime.js b/src/runtime.js
index d9e1fe5c994030f40461167faac8b3df4d60ff22..d4849d9b131fcaea70efbadbe5cf64b39c460502 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -576,6 +576,15 @@ function ToInt32(x) {
   return %NumberToJSInt32(ToNumber(x));
 }
 
+// ES6, section 7.1.15
+function ToLength(x) {
+  if (%_IsSmi(x) && x > 0) return x; // not >= since -0 >= +0

[mathias, 2014/09/18 06:16:32]

Same here.

[Dmitry Lomov (no reviews), 2014/09/18 06:26:46]

if %_IsSmi(x) then x can only be +0  (-0 is not Smi). Feel free to do: 
    if (%_IsSmi(x)) return (x > 0 ? x : 0); 
All Smis are safe

+
+  var len = ToInteger(x);
+  if (len <= 0) return 0;
+  return MathMin(len, $Number.MAX_SAFE_INTEGER);
+}
+
 
 // ES5, section 9.12
 function SameValue(x, y) {
@@ -590,6 +599,15 @@ function SameValue(x, y) {
   return x === y;
 }
 
+// ES6, section 7.2.4
+function SameValueZero(x, y) {
+  if (typeof x != typeof y) return false;
+  if (IS_NUMBER(x)) {
+    if (NUMBER_IS_NAN(x) && NUMBER_IS_NAN(y)) return true;
+  }
+  return x === y;
+}
+
 
 /* ---------------------------------
    - - -   U t i l i t i e s   - - -