has-symbols 
Determine if the JS environment has Symbol support. Supports spec, or shams.
Example
var hasSymbols = require('has-symbols');
hasSymbols() === true; // if the environment has native Symbol support. Not polyfillable, not forgeable.
var hasSymbolsKinda = require('has-symbols/shams');
hasSymbolsKinda() === true; // if the environment has a Symbol sham that mostly follows the spec.
Supported Symbol shams
Tests
Simply clone the repo, npm install, and run npm test