es6.function.name.js 524 Bytes
var setDesc    = require('./$').setDesc
  , createDesc = require('./$.property-desc')
  , has        = require('./$.has')
  , FProto     = Function.prototype
  , nameRE     = /^\s*function ([^ (]*)/
  , NAME       = 'name';
// 19.2.4.2 name
NAME in FProto || require('./$.descriptors') && setDesc(FProto, NAME, {
  configurable: true,
  get: function(){
    var match = ('' + this).match(nameRE)
      , name  = match ? match[1] : '';
    has(this, NAME) || setDesc(this, NAME, createDesc(5, name));
    return name;
  }
});