$ npm install with

js
var addWith = require('with')

addWith('obj', 'console.log(a)')
// => ';(function (console, a) {
//       console.log(a)
//     }("console" in obj ? obj.console :
//                          typeof console!=="undefined" ? console : undefined,
//       "a" in obj ? obj.a :
//                    typeof a !== "undefined" ? a : undefined));'

addWith('obj', 'console.log(a)', ['console'])
// => ';(function (console, a) {
//       console.log(a)
//     }("a" in obj ? obj.a :
//                    typeof a !== "undefined" ? a : undefined));'

js
with (obj) {
  src
}

js
var foo = 'foo'
with ({}) {
  foo = 'bar'
}
assert(foo === 'bar')// => This fails for compile time with but passes for native with

var obj = {foo: 'foo'}
with ({}) {
  foo = 'bar'
}
assert(obj.foo === 'bar')// => This fails for compile time with but passes for native with

js
if (foo === undefined)

js
if (typeof foo === 'undefined')