We have been building DevTools to target Chrome 49 and Firefox 54. These are super old browser versions and they did not have full ES6 support, so the generated build is more bloated than it needs to be.
DevTools uses most modern language features. Off the top of my head, we it uses basically everything but async and generator functions.
Based on CanIUse charts– I believe that in order to avoid unnecessary polyfill/wrapper code being generated, we'd need to target Chrome 60+ (released 2017-07-25) and Firefox 55+ (released 2017-04-18). This seems like a reasonable set of browsers to target.
Note that we can't remove the IE 11 target from the react-devtools-core backend yet due to Hermes (React Native) ES6 support but that should be doable by the end of the year given current engineering targets. But we could update the frontend target, as well as the targets for the extensions and the react-devtools-inline package.
This commit increases the browser targets then for Chrome (from 49 to 60) and Firefox (from 54 to 55)
* update all facebook.github.io links
* facebookincubator links : update some outdated links and fix two other broken links where they are actually the latest updated ones
DevTools isn't being downloaded like typical JavaScript, so bundle size concerns don't apply. Parsing is still a consideration (so I'm open for discussion here) but I think this change would provide a couple of benefits:
* People are more likely to *actually read* non-minified source code when e.g. a breakpoint is hit (as with the recent debugger statement)
* Component stacks will be easier to parse on bug reports
This commit adds a new tab to the Settings modal: Debugging
This new tab has the append component stacks feature and a new one: break on warn
This new feature adds a debugger statement into the console override
* DevTools console override handles new component stack format
DevTools does not attempt to mimic the default browser console format for its component stacks but it does properly detect the new format for Chrome, Firefox, and Safari.
* Enable prefer-const rule
Stylistically I don't like this but Closure Compiler takes advantage of
this information.
* Auto-fix lints
* Manually fix the remaining callsites
Update various parts of DevTools to account for the fact that the global "hook" might be undefined if DevTools didn't inject it (due to the page's `contentType`) it (due to the page's `contentType`)
Brian Vaughn