runInContext  source npm
_.runInContext([context=root])
Create a new pristine lodash function using the given context object.
Arguments
- [context=root] (Object) The context object. 
Returns (Function)
 Returns a new lodash function.
Example
_.mixin({ 'foo': _.constant('foo') });
var lodash = _.runInContext();
lodash.mixin({ 'bar': lodash.constant('bar') });
_.isFunction(_.foo);
// => true
_.isFunction(_.bar);
// => false
lodash.isFunction(lodash.foo);
// => false
lodash.isFunction(lodash.bar);
// => true
// using `context` to mock `Date#getTime` use in `_.now`
var mock = _.runInContext({
  'Date': function() {
    return { 'getTime': getTimeMock };
  }
});
// or creating a suped-up `defer` in Node.js
var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;