4 files changed, 32 insertions, 0 deletions
diff --git a/platform/android/src/style/android_conversion.hpp b/platform/android/src/style/android_conversion.hpp
index e2b2685928..790c82a1c0 100644
--- a/platform/android/src/style/android_conversion.hpp
+++ b/platform/android/src/style/android_conversion.hpp
@@ -66,6 +66,15 @@ inline optional<float> toNumber(const mbgl::android::Value& value) {
     }
 }
 
+inline optional<double> toDouble(const mbgl::android::Value& value) {
+    if (value.isNumber()) {
+        auto num = value.toDouble();
+        return num;
+    } else {
+        return {};
+    }
+}
+
 inline optional<std::string> toString(const mbgl::android::Value& value) {
     if (value.isString()) {
         return value.toString();
diff --git a/platform/darwin/src/MGLConversion.h b/platform/darwin/src/MGLConversion.h
index d51ebd775c..d6363b28eb 100644
--- a/platform/darwin/src/MGLConversion.h
+++ b/platform/darwin/src/MGLConversion.h
@@ -104,6 +104,14 @@ inline optional<float> toNumber(const id value) {
     }
 }
 
+inline optional<double> toDouble(const id value) {
+    if (_isNumber(value)) {
+        return ((NSNumber *)value).doubleValue;
+    } else {
+        return {};
+    }
+}
+
 inline optional<std::string> toString(const id value) {
     if (_isString(value)) {
         return std::string(static_cast<const char *>([value UTF8String]));
diff --git a/platform/node/src/node_conversion.hpp b/platform/node/src/node_conversion.hpp
index 22daedef6a..d266745548 100644
--- a/platform/node/src/node_conversion.hpp
+++ b/platform/node/src/node_conversion.hpp
@@ -82,6 +82,14 @@ inline optional<float> toNumber(v8::Local<v8::Value> value) {
     return value->NumberValue();
 }
 
+inline optional<double> toDouble(v8::Local<v8::Value> value) {
+    Nan::HandleScope scope;
+    if (!value->IsNumber()) {
+        return {};
+    }
+    return value->NumberValue();
+}
+
 inline optional<std::string> toString(v8::Local<v8::Value> value) {
     Nan::HandleScope scope;
     if (!value->IsString()) {
diff --git a/platform/qt/src/qt_conversion.hpp b/platform/qt/src/qt_conversion.hpp
index 4b93ca7423..40d7e5b928 100644
--- a/platform/qt/src/qt_conversion.hpp
+++ b/platform/qt/src/qt_conversion.hpp
@@ -83,6 +83,13 @@ inline optional<float> toNumber(const QVariant& value) {
         return {};
     }
 }
+inline optional<double> toDouble(const QVariant& value) {
+    if (value.type() == QVariant::Int || value.type() == QVariant::Double) {
+        return value.toDouble();
+    } else {
+        return {};
+    }
+}
 
 inline optional<std::string> toString(const QVariant& value) {
     if (value.type() == QVariant::String) {