On 19/11/2013 1.38, Nikhil Marathe wrote: > DOM Promise has been in the tree for a while > We currently have two JS promise implementations in our codebase: > toolkit/modules/Promise.jsm
Though it may seem counter-intuitive, the non-native Promise.jsm has grown better error reporting and debuggability, and maybe even better performance (depending on whether DOM Promises are optimized for not returning to the outer OS event loop when resolving promise chains). I just used the debuggability features to find a pending promise handler that was causing a memory leak today, and I've taken screenshots: https://developer.mozilla.org/Mozilla/JavaScript_code_modules/Promise.jsm/Promise#Debugging I hope to see a comparable or even better level of debuggability in the native Promise implementation soon! In the meantime, I think we should switch Promise.jsm consumers to use the new style of constructor (bug 941757), so that we'll not need to do any change to the code when DOM Promises are ready to replace Promise.jsm. > addon-sdk/source/lib/sdk/core/promise.js I think we should continue the ongoing work to convert users of this non-conforming implementation to Promise.jsm. This is the most difficult part because the code following "then" is often executed after the registered callbacks, on a fulfilled or rejected promise. To recap, I think these can proceed in parallel: * Implement new Promise.jsm constructor and covert consumers * Improve DOM Promise debuggability, then replace Promise.jsm * Make promise.js users compatible with Promise.jsm / DOM promises Cheers, Paolo _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
