expressions working

Signed-off-by: Casey Lee <cplee@nektos.com>

vendor/github.com/robertkrimen/otto/value_boolean.go

@@ -0,0 +1,43 @@
+package otto
+
+import (
+	"fmt"
+	"math"
+	"reflect"
+	"unicode/utf16"
+)
+
+func (value Value) bool() bool {
+	if value.kind == valueBoolean {
+		return value.value.(bool)
+	}
+	if value.IsUndefined() {
+		return false
+	}
+	if value.IsNull() {
+		return false
+	}
+	switch value := value.value.(type) {
+	case bool:
+		return value
+	case int, int8, int16, int32, int64:
+		return 0 != reflect.ValueOf(value).Int()
+	case uint, uint8, uint16, uint32, uint64:
+		return 0 != reflect.ValueOf(value).Uint()
+	case float32:
+		return 0 != value
+	case float64:
+		if math.IsNaN(value) || value == 0 {
+			return false
+		}
+		return true
+	case string:
+		return 0 != len(value)
+	case []uint16:
+		return 0 != len(utf16.Decode(value))
+	}
+	if value.IsObject() {
+		return true
+	}
+	panic(fmt.Errorf("toBoolean(%T)", value.value))
+}