Advantages of WCF Web API over WCF REST service

I already have a WCF service that communicates through SOAP messages now I have a requirement to modify this service such that it can be consumed from JavaScript. The client asked me to look into WCF Web Api. I don't understand what are advantages I'm going to get using WCF Web Api than WCF RESTful services. Is WCF RESTful services is enough开发者_运维问答 for this job?

WCF Web API is evolution of current WCF REST services = it will be the next version of WCF REST but at this time it is still preview.