The Internet of Things (IoT) is a network of physical, heterogeneous, connected devices providing services through private networks and the Internet. It connects a range of new devices to the Internet so they can communicate with Web servers and other devices around the world. Today's standard platform for communicating Web pages and Web apps is JavaScript (JS) and extending the same standard platform to connect IoT devices seems more than appropriate. However, porting JS applications to the large variety of IoT devices, specifically on System-on-a-Chip (SoCs) devices (e.g., Arduino Uno, Particle Photon), is challenging because these devices are constrained in terms of memory and storage capacity. Running JS applications adds an overhead of resources to deploy a code interpreter on the devices. Also, running JS applications may not be possible "as is" on some device missing some hardware/software capabilities. To address this problem, we propose MoMIT a multiobjective optimization approach to miniaturize JS applications to run on IoT constrained devices. To validate MoMIT, we miniaturize a JS interpreter to execute a testbed comprised of 23 applications and measure their performances before and after applying the miniaturization process. We implement MoMIT using three different search algorithms and found that it can reduce code size, memory usage, and CPU time by median values of 31%, 56%, and 36% respectively. Finally, MoMIT ported the miniaturized JS interpreters up to to 2 SoCs additional devices, in comparison of using default JS interpreter features.