Quick Start Best Practices - Proper way to call init() on start up - E.on() - onInit() - delayed start - Sample code usage examples

Fri 2020.01.17

While I can not take any credit for these examples, having a launching point is needed to save precious moments supporting our Espruino community.

These individuals were cranking out init code solutions two years before I could spell Espruino:

@Ollie post #2

http://forum.espruino.com/comments/12661691/

@MaBe post #3

http://forum.espruino.com/comments/12662272/

@Gordon post #4

http://forum.espruino.com/comments/12662708/

@allObjects post #8 his 0.02 worth

http://forum.espruino.com/comments/12663321/

and a must read post #18 two more 0.02 worth

http://forum.espruino.com/comments/12727109/

EDIT: See @MaBe solution in #2 post to conditionally select during development

The basic idea:

// Note: save() must be entered at least once before this will take effect

E.on( 'init', function() {
  setTimeout( function() {
    console.log( "Hello World!" );
  }, 1500 );
});


// or


// Will get called automatically
function onInit() {
}

An excellent read with usage examples, the entire article:

simple explanation how to save code

a must read explanation

http://www.espruino.com/Saving

and another @allObjects gem

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

this is what I use now:

// global vars
var release = false;
......
// functions, classes .....
......
// this will be called on power up, if code was saved
onInit(){ ... }

if (release) {
      // save code to flash, to make code permanent
      setTimeout(save,1E3); 
} else {
      // or just start onInit, typical way if you are still developing and testing
      setTimeout(onInit,1E3); 
}

Edit: added missing curly bracket open in line 12

...opening curly brace - in line 12 - fell victim to the experience that allows writing code top of your head without testing... (EDIT: obviously fixed now). I like this variable option. Put it as a single line with (could not let go my 'Schnapszahl'):

setTimeout((release)?save:onInit,999);

I use a similar approach for my debugging, logging:

• have a variable each for enabling / disabling it, for example lon for log is on
  
• a log() that invokes console.log(arguments); to save space
  
• invoking on one line `if (lon) log(...); to filter for final load
  
  

In (my) emulation I have an overwrite that logs way much more...

It is always a good approach to keep code changes the smallest between dev and release... last but not least also to be able to fall back in case debug is needed without having to change code but just the value of a variable.

Sun 2020.01.19

ref: code snippets in post #2 and post #3

And we now have a practical working example solution using the Ternary operator

condition ? exprIfTrue : exprIfFalse

explanation and examples

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Conditional_Operator

https://codeburst.io/javascript-the-conditional-ternary-operator-explained-cac7218beeff