a strict deep-extend that can handle cyclic structures
npm install cyclic-deep-extenda strict deep-extend that can handle cyclic structures
``javascript
var deepExtend = require('cyclic-deep-extend');
var a = {},
b = {};
b.b = b;
deepExtend(a, b);
a.b === b;
a.b.b.b.b.b.b === b; // etc...
``