How to have ONE codebase that works after both direct upload and save() with power cycle (run in no-save AND save mode)

[espruino-discuss2]

Posted at 2017-02-09 by @allObjects

This tutorial was triggered by the forum post about [code not running after save() and power cycle]
(http://forum.espruino.com/comments/13437285/) and related response, which states:

It's often not practical to make code that works both after direct upload and after save() and restart

Conclusion and recommendation: ...indeed... therefore, always choose the format that works for/after save()... to be on the safe side.

But this is a bit cumbersome while developing, because you need to save the uploaded code every time and do a power-cycle - un-plug and re-plug - to get the code started. To get around this and speed up development, use this stream lined development process.

• 1. Use function onInit() { ... } rather than E.on('init', function(){ ... });, and start your code after uploading by entering onInit() in the console / left hand pane of the Espruino Web IDE.

Having to enter onInit() in the console every time after upload of the code to start it is still somewhat cumbersome, therefore

• 2. Add - for development time - setTimeout(onInit,500); as last line in your code, which makes your overall code structure look like this:

// ... your application code
// ...
// ...

// initialization / start-up code
function onInit() {
 // ...
}

// convenience line for dev phase; REMOVE for final save() and normal runtime
setTimeout(onInit,500);

This last line starts your code automatically after upload has completed in the same way as later on a power cycle will restart it on normal runtime after power cycle / reset. The timeout is added to allow - on the Espruino side - the upload process to complete and do so decoupled from your code start / execution.

• 3. REMOVE this last line setTimeout(onInit,500); when entering the final development phase where you test save() and power-cycling.

Bonus for using setTimeout(onInit, ...:

You can pass development time parameters

setTimeout(onInit, 500, true, "otherRuntimeParm_mode"); // enable debug, etc.

that overwrite runtime parameters - for example for debugging w/ console output while developing - which automatically go away for the normal runtime. Your overall code may then look something like this complete code template good for code running after both direct upload AND save() :

Code Template for development AND runtime:

var dbg = false; // ***d***e***b***u***g*** of for normal runtime
var mode = "normal"; // other runtime parameter
// ...

// your app code using global ```dbg``` and ```mode``` runtime vars to
// control debug/normal runtime behavior, for ex. console output, etc.
// ...
   if (dbg) console.log("....");
// ...

// initialization / start-up code
function onInit(dbgParm, otherParm_mode, ...) {

  // accepting / overwriting operation parms while under development
  dbg = dbgParm;
  mode = (mode === undefined) ? mode : otherParm_mode;

  // other initialization / startup code
  // ...
}

// convenience line for dev phase; REMOVE for final save() and normal runtime
setTimeout(onInit, 500, true, "otherRuntimeParm_mode"); // enable debug, etc.