Hi Sam, Thanks for explaining. The each_pair method works great.
Your commentary on javascript and ecma standard is fascinating. Sadly, I do not have the energy to keep up with it all. Craig > On Jun 27, 2020, at 3:13 PM, Sam Ruby <ru...@intertwingly.net> wrote: > > On Sat, Jun 27, 2020 at 3:49 PM Craig Russell <apache....@gmail.com> wrote: >> >> I'm having some trouble with the memstat.rb.js code, specifically with the >> committer.forms implementation. [1] >> >> I'm guessing that the implementation of hashes in the rb->js compiler is >> inconsistent with my usage of it. > > There are two separate problems here. > > The first problem is that Ruby2JS is not smart enough to know that > committer_forms is a hash, so it maps each to forEach, which is the > common use case. However, each_pair is a method that > is unique to hashes, so you can do what you want merely by > substituting each_pair for each. > > https://apidock.com/ruby/Hash/each_pair > > Next, if you look at the code that is generated, it basically compiles > it to the code that works[1], as that is the best that you can do with > JavaScript that runs across all browsers (including Internet Explorer > and Opera mini). > > In 2017, ECMAScript introduced Object.entries which lets you get > access to key value pairs: > > https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries > https://caniuse.com/#feat=object-entries > > .If you were to enable es2017 (or later) support, ruby2js will make us > of Object.entries. You can enable es2017 support by adding the > following line to the application: > > require 'ruby2js/es2017' > >> Thanks, >> Craig > > - Sam Ruby > >> [1] >> This code works: >> >> for form in committer.forms >> link = committer.forms[form] >> console.log("#{form}: #{link}") >> >> [Log] icla: >> https://svn.apache.org/repos/private/documents/iclas/craig-russell.pdf >> (app.js, line 4057) >> [Log] member: >> https://svn.apache.org/repos/private/documents/member_apps/craig-l-russell.pdf >> (app.js, line 4057) >> [Log] emeritus_rescinded: >> https://svn.apache.org/repos/private/documents/emeritus-requests-rescinded/craig-l-russell.txt >> (app.js, line 4057) >> >> This code compiles but fails at execution time: >> >> committer.forms.each do |form, link| >> console.log("#{form}: #{link}") >> end >> >> TypeError: committer.forms.forEach is not a function. (In >> 'committer.forms.forEach(function(form, link) { >> console.log(form + ": " + link) >> })', 'committer.forms.forEach' is undefined) >> >> Craig L Russell >> c...@apache.org >> Craig L Russell c...@apache.org
