Javascript multiple assignment

Question

What means that code?

function myConnectController($state, $my, myService, apiJobs, apiMy) {
  var ctrl = this, mySequenceDataService; // this statement
  ...
  function init() {
    mySequenceDataService = $my.mySequenceDataServiceFactory.createInstance({
  ...
  });}
  ...
}

Is that some kind of inheritance?

That `var` declaration declares two variables: one called "ctrl" and one called "mySequenceDataService". — Pointy, Jul 04 '18 at 14:19
@Pointy then what's value of `mySequenceDataService` variable? — Qback, Jul 04 '18 at 14:20
at that point is has no value. the value is set on this line mySequenceDataService = $my.mySequenceDataServiceFactory.createInstance({ ... });} — locomain, Jul 04 '18 at 14:22
It's `undefined` because it is not initialized (at least not in the code you posted). — Pointy, Jul 04 '18 at 14:24

score 2 · Answer 1 · answered Jul 04 '18 at 14:23

var within a function declares a (local) variable.

You can "chain" assignments after one var keyword by comma seperating them.

var ctrl = this, mySequenceDataService;
               ^// comma seperating variables

In this example mySequenceDataService is assigned undefined, but is local and will not try to look in other scopes or the global scope for a variable named like that, nor assign the value(which happens in your init method) to a global scope variable.

you can also do this:

 var foo = 'hello', baz = 'world', bal = 'universe';

Javascript multiple assignment

1 Answers1