Does Swift provides the ability to eval Swift code like Javascript does?

Does Swift provides the ability to eval Swift code like Javascript does? I would like to create an app that can run Swift code.

Is swift similar to JavaScript?

There are numerous similarities between both JavaScript and Swift. There are some minor differences but their essence is the same. As compared to JavaScript, Swift provides a lot of advancements in syntax. Of course (arguably) it can be said that the more features a language provides, the more trouble it can create.

How do I run a swift code?

If you've installed the latest version of Xcode you should have a swift command available in your terminal, which launches a Swift REPL 1. You can run the Swift REPL from the command line and enter Swift code directly into it. Whenever you enter valid Swift code in the REPL, it will immediately compile and run it.

No, it doesn't. There is a Swift JIT exposed via the REPL, but it's not (currently at least) intended for use in applications.