/**

* Module exports.
*/

module.exports = deprecate;

/**

* Mark that a method should not be used.
* Returns a modified function which warns once by default.
*
* If `localStorage.noDeprecation = true` is set, then it is a no-op.
*
* If `localStorage.throwDeprecation = true` is set, then deprecated functions
* will throw an Error when invoked.
*
* If `localStorage.traceDeprecation = true` is set, then deprecated functions
* will invoke `console.trace()` instead of `console.error()`.
*
* @param {Function} fn - the function to deprecate
* @param {String} msg - the string to print to the console when `fn` is invoked
* @returns {Function} a new "deprecated" version of `fn`
* @api public
*/

function deprecate (fn, msg) {

if (config('noDeprecation')) {
  return fn;
}

var warned = false;
function deprecated() {
  if (!warned) {
    if (config('throwDeprecation')) {
      throw new Error(msg);
    } else if (config('traceDeprecation')) {
      console.trace(msg);
    } else {
      console.warn(msg);
    }
    warned = true;
  }
  return fn.apply(this, arguments);
}

return deprecated;

}

/**

* Checks `localStorage` for boolean values for the given `name`.
*
* @param {String} name
* @returns {Boolean}
* @api private
*/

function config (name) {

// accessing global.localStorage can trigger a DOMException in sandboxed iframes
try {
  if (!global.localStorage) return false;
} catch (_) {
  return false;
}
var val = global.localStorage[name];
if (null == val) return false;
return String(val).toLowerCase() === 'true';

}