There's a formal syntax for jsdoc strings which you should follow:
https://developers.google.com/closure/compiler/docs/js-for-compiler

We're in the process of getting dygraphs to compile under the Closure Compiler, so we'd really like to keep new jsdoc formally correct.

This should be:

/**
 * @param {string} name The name the data handler ...
 * @param {!Dygraph.DataHandler} handler DataHandler implementation...
 */