The light bundle of vis.js (vis-light.js or vis-light.min.js) don't have the external dependencies of moment.js and hammer.js bundled. You have to load these yourself before loading vis-light.js. This is useful in the case that your application is using moment.js and/or hammer.js itself too, in order not to load these libraries twice. Note that it is possible too to create your own vis.js bundle: the source code consists of common.js modules which is browserifiable.