mapshaper
Introduction
mapshaper is written by Matthew Bloch using node.js. It can edit Shapefile, GeoJSON, TopoJSON, CSV etc.
With echarts map editing process, it is mainly used to wipe out internal borders.
Installation
npm install -g mapshaper
The most important command for echarts map editing
mapshaper your_shape_with_internal_borders.geojson -dissolve2 -o your_shape_contoure.geojson