Injecting local variables into functions (for people with zero moral boundaries)

inject_local_vars.js

Function.prototype.with = function () {
  
  // No local variables are defined to prevent scope pollution,
  // cuz `eval` can see 'em.
  // `with` turns object properties into local variables.
  with (arguments[0] || {}) {

    // Turn the function into a string, then eval it as an expression.
    return eval(`(${String(this)})`).call(
      // Invoke it and apply the `this` and `arguments` params.
      ...([].slice.call(arguments).slice(1))
    )
  }
}

/*
(function () {
  console.log(local) // Scoped data! Yeah!
}).with({ local: 'Scoped data! Yeah!', fired: 'probably' })

*/