Version 2.0.0

Change the api

var booleanExpression = require('boolean-expression')
var expression = booleanExpression('foo && bar && !qux')
expression.toString()
// returns `foo && bar && !qux`

expression.toString(function (e) {
  return `~val.indexOf(${JSON.stringify(e)})`
})
// returns ~val.indexOf("foo") && ~val.indexOf("bar") && ! ~val.indexOf("qux")

expression.toTokens()
// returns ['foo', 'bar', 'qux']