extract-vars is a unique library that helps to extract variables from a javascript expression that could be possibly watched.
In spite of its light weight extract-vars is a pretty powerful library. You can combine it with AsyncWatch and achieve a very performant watcher.
THe library is written to support 2-way binding framework development.
It is written in beautiful typescript, so you get typings along once installed.
Features
- Extracts all watchable variables from a string exression
- Uses a solid test set
- Does not use RegEx at all (hence costs nothing)
- Typings for typescript included
- Universal dist.js (works on both frontend and server)
Use cases
Variable "dig" is exposed to window.
Extracts variables that should be watched. (imagine ng-class case)
dig(`{"active" : user.name === 'hello', disabled : !user.age > 18 && user.sex === 1}`)
// ["user.name", "user.age", "user.sex"]
Variable assignment, declaration are ignored as for one cannot watch them.
dig(`user.getFullName(user.name, "hello") user.age; var a = "111";e`)
// ["user.name", "user.age"]
Submit an issue if you find a bug.
Star it you like it.