hasten

Evaluate JS statically and dynamically. Hasten resolves all it can statically and asks for your input when it can't.

api

Give it input and it will give you output:

const output = hasten(src)

Give it variables and it will use those while resolving stuff:

const output = hasten(src, {
  foo: 'baz'
})

Give it a callback and it will call it when it cant resolve something. Now you can return something to help hasten resolve:

const output = hasten(src, {
  foo: 'baz'
}, (astNode, missingAstNode) => {
  if (astNode.type === 'ifStatement' && missingAstNode.name === 'device') {
    return 'phone'
  }
})

example

Input:

const obj = {}
obj.foo = 'bar'
if (obj.foo === 'bar') {
  console.log('success!')
}
if (/Macintosh/.test(window.navigator.userAgent)) {
  console.log('hipster!')
}
if (unknownThing === 'superman') {
  console.log('superman!')
}

Do something like:

const output = hasten(src, {
  window: {
    navigator: {
      userAgent: "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.98 Safari/537.36"
    }
  }
}, (astNode, missingAstNode) => {
  if (missingAstNode.name === 'unknownThing') {
    return 'bird'
  }
}

Output:

const obj = {}
obj.foo = 'bar'
if (true) {
  console.log('success!')
}
if (true) {
  console.log('hipster!')
}
if (false) {
  console.log('superman!')
}