v2.0.0

• Add d3.chordDirected. #3
• Add d3.chordTranspose.
• Add d3.ribbonArrow.
• Add ribbon.padAngle.
• Add ribbon.sourceRadius.
• Add ribbon.targetRadius.
• Mark the package as having no side effects. Thanks, @stof! #11
• Use exact paths in imports. d3/d3#3265
• Use explicit files when publishing. d3/d3#3335
• Standardize dependencies. d3/d3#3337
• Remove d3-array dependency.

This release adopts ES2015 language features such as for-of and drops support for older browsers, including IE. If you need to support pre-ES2015 environments, you should stick with d3-chord 1.x or use a transpiler.