Function toNumber

static/vuejs/vue.js:29–32

* Convert a input value to a number for persistence. * If the conversion fails, return original string.

(val)

 * If the conversion fails, return original string.
 */
function toNumber (val) {
  var n = parseFloat(val);
  return isNaN(n) ? val : n
}

/**
 * Make a map and return a function for checking if a key