It appears that I get an editor warning ‘Map’ is not defined when I use the delightfully useful ES6 Map object
The code executes fine so perhaps this just needs to be added to the editor’s JS Object/Keyword list?
Yes, it’s just a linting warning, your code will still work if it’s valid. As a temporary workaround, you can add /* global variableName */ (http://eslint.org/docs/user-guide/configuring#specifying-globals) and the warning will go away.
/* global variableName */