• Halt when -merge-layers fails
• Print a warning if -innerlines output is null
• Apply snapping after multiple import files are merged/combined
• Let users apply arbitrarily large snap intervals instead of capping at avg. segment length
• Use APIError type for invalid API function call parameters
• Switch from async csv parsing using node-csv to synchronous parsing using d3.dsv
• Merge mapshaper.runCommandString() into mapshaper.runCommands()
• Add mapshaper.applyCommands() to tranform Geo/TopoJSON programmatically.