afcondon/simpleJS2PS.md Secret

## simpleJS2PS.md

      
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              simpleJS2PS.md
            
          
    Making a Purescript function available to JS web app

Requirements


node / npm installation
install bower using npm
purescript tools available on your $PATH
(fine to just unload the tar.gz into /usr/local/bin or whatever or npm -g install purescript and pulp)

Create a simple program and test it


$ mkdir foo; cd foo; pulp init
pulp run
should see the familiar $ Hello sailor!
see footer for other ways of running this program outside of a browser, or...move on to making it a webapp

Create minimal web app


$ mkdir dist; cd dist
make a minimal index.html in this dist directory

<!DOCTYPE html>
<html lang="en">
 <head>
     <meta charset="UTF-8">
 </head>
 <body>
     <script src="app.js" charset="utf-8"></script>
     <script>
       document.addEventListener('DOMContentLoaded', function () {
           PS.Main.main();
       });
     </script>
  </body>
 </html>
penultimate step: make the app.js referenced above


back up in top level dir we use psc-bundle to make browser-ready bundle
$ psc-bundle output/**/*.js -m Main > dist/app.js
note that we use -m Main to identify a module that we want to include
but we don't give psc-bundle a --main Main option: we don't want the mainline called automatically

final step, serve this app


it's enough to do $ cd dist; python -m SimpleHTTPServer
load page as http://localhost:8000 - you should see the "Hello, sailor!" on the JS console

verify that your main function is callable from console in browser debugger


you should be able to do > PS.Main.main() to call this mainline
note that currying means you need to call multiparam functions explicitly (> PS.Main.otherfunc(p1)(p2))

FOOTER: bonus points try it in psci and node


you can run this tiny program in a Purescript REPL by doing $ pulp psci. You have to import - at a minimum - the Main module which you can simply do as > import Main which allows you to then do > main and see your "Hello, sailor!" logged out.
<TBA - how to run this from within a node REPL or script>