November 21st

@amelzer, @yurydelendik, @nyrosmith, @Fischer-L, @jasonLaster, @codehag, @jselmani, @jacobjzhang, @ryanjduffy, @khal0988, @cjwsstrm, @jainsneha23, @assafdd, @bogas04, @cvetanovskaa, @Outpox, @varenya, @James300, @GarethSharpe, @bomsy

Source Maps

Yury completed a prototype of scope and variable mapping. The proof of concept maps let and const variables from the generated scope into original scopes. This builds on the work to map minified variables where original variable names and original variable names are swapped at runtime. We think that we will be able to cover additional cases in 2018 so that users see the original variable names and values when they’re paused! PR

Johnny helped us address a big question when viewing original code: “is it original” and “where is the bundle”? We now show a link at the bottom of the footer to the bundle. PR

Mapping Scopes

Pretty Print

Last week Sneha helped us disable irrelevant Editor context menu items. This week, she helped us re-enable “Jump to Generated Location” and “Jump to mapped Location” for pretty printed files. PR

Assaf hacked on pretty printing last week and it’s now much better! The debugger now auto-pretty-prints minified sources. We’ll have a preference for disabling it next week. PR. The debugger also upgraded acorn, which has support for pretty printing template strings. PR @assafdd

Pretty Print - Context Menu

Framework Features

James added the react logo to source tabs when there is a react component in the file. PR

React Tab


We had some improvements in the UI to make rendering faster and easier to navigate, as well as giving more information to a new user. Varenya, a new contributor, has introduce a new loading message, so that searches that take a longer time do not seem like they are broken. PR @varenya

We also improved the UI of the pause on exception button. Before it was a button with three states, it has been changed into a dropdown by Gareth Sharpe PR @GarethSharpe

Outline View


Last week, we noticed that when we added JSX syntax highlighting we introduced a 10% slow down with source loading. This came from React differentiating between empty objects in Redux-Connect. Jason fixed the issue and we’re now on alert for new performance related regressions with the amazing Damp tool! PR

Close Buttons



Since so many members of the community are doing talks about the debugger, we have added a talks page, to make it easier to find and watch. PR @jasonLaster. The talks range from what we are currently doing, what we would like to do and what might happen in the future.

We also introduced documentation around performance, so that any new contributors interested in working on perf issues have a place to start. PR @jasonLaster




Code Health

More focus has been placed on refactoring mapDispatchToProps, which will clean up our debugging scopes and also removed a lot of unnecessary functions and make it easier to see where certain actions are coming from. It is more typing, but also more explicit. Thanks to Fischer-L and amelzer for that PR PR