Standardized Debug

This proposal is at Stage 1 of the TC39 Process.


Different environments expose different APIs for interacting with debugger facilities. Some of them do not expose any APIs for this at all. This proposal aims to provide standardized debugging facilities across all ECMAScript implementations. Additionally, the APIs are constrained to be identity functions - that is, they return the value which is passed to them.

This proposal suggests adding the following meta-property-functions to ES:

  • debugger.log ( v )
  • debugger.break ( [ v ] )

Note that, like import(), they are only valid in call expression form. For example, x().then(debugger.break) would be invalid. You would have to do x().then((v) => debugger.break(v)). This limitation is in place to ensure these methods (particularly break) are only ever invoked from ECMAScript code.