v4.0.0

Changes:

• removing ask and generate helpers from api, to keep runjs codebase more focused about its main purpose
• dropping support for node < 6.11.1
• support for other than Babel transpilers, like TypeScript
• log option to run function, when false it does not log the command
• documentation updates
• support for async/await
• option helper

Migration from 3.x to 4.x procedure:

• make sure you have node version >=6.11.1
• if you use Babel you need to add "runjs": {requires: ["./node_modules/babel-register"]} config to your package.json, otherwise Babel transpiler won't be picked up
• find alternatives for ask and generate, those are not supported by runjs anymore