node-supports-preserve-symlinks-flag 
Determine if the current node version supports the --preserve-symlinks flag.
Example
var supportsPreserveSymlinks = require('node-supports-preserve-symlinks-flag');
var assert = require('assert');
assert.equal(supportsPreserveSymlinks, null); // in a browser
assert.equal(supportsPreserveSymlinks, false); // in node < v6.2
assert.equal(supportsPreserveSymlinks, true); // in node v6.2+Tests
Simply clone the repo, npm install, and run npm test