[js] Optimize boolification.

Author: pmurias

src/vm/js/Compiler.nqp

@@ -536,11 +536,13 @@ class QAST::CompilerJS does DWIMYNameMangling does SerializeOnce {
             }
 
             if $got == $T_OBJ {
+                if $desired == $T_BOOL {
+                    return Chunk.new($desired, "{$chunk.expr}.\$\$decont($*CTX).\$\$toBool($*CTX)", [$chunk]);
+                }
                 my %convert;
                 %convert{$T_STR} := 'toStr';
                 %convert{$T_NUM} := 'toNum';
                 %convert{$T_INT} := 'toInt';
-                %convert{$T_BOOL} := 'toBool';
                 return Chunk.new($desired, 'nqp.' ~ %convert{$desired} ~ '(' ~ $chunk.expr ~ ", {$*CTX})", [$chunk]);
             }
 

src/vm/js/nqp-runtime/null.js

@@ -3,5 +3,8 @@ class Null {
   $$decont(ctx) {
     return this;
   }
+  $$toBool(ctx) {
+    return 0;
+  }
 };
 module.exports = new Null();

src/vm/js/nqp-runtime/runtime.js

@@ -195,27 +195,6 @@ exports.toInt = function(arg, ctx) {
   }
 };
 
-exports.toBool = function(maybeContainer, ctx) {
-  if (maybeContainer == Null) {
-    return 0;
-  }
-  var value = maybeContainer.$$decont ? maybeContainer.$$decont(ctx) : maybeContainer;
-  if (typeof value == 'number') {
-    return value ? 1 : 0;
-  } else if (typeof value == 'string') {
-    return value == '' ? 0 : 1;
-  } else if (value == Null) {
-    return 0;
-  } else if (value.$$toBool) {
-    return value.$$toBool(ctx);
-  } else if (typeof value == 'function') {
-    // needed for continuations
-    return 1;
-  } else {
-    throw "Can't decide if value is true";
-  }
-};
-
 exports.intToObj = function(hllName, i) {
   var currentHLL = hll.hllConfigs[hllName];
   var type;
@@ -391,10 +370,23 @@ Number.prototype.$$decont = function(ctx) {
   return this;
 };
 
+Number.prototype.$$toBool = function(ctx) {
+  return this === 0 ? 0 : 1;
+};
+
 String.prototype.$$decont = function(ctx) {
   return this;
 };
 
+String.prototype.$$toBool = function(ctx) {
+  return this === '' ? 0 : 1;
+};
+
+// needed for continuations
+Function.prototype.$$toBool = function(ctx) {
+  return 1;
+};
+
 
 exports.null_s = null_s;
 exports.Null = Null;