Changing dependencies during the load process.

John Barton johnjbarton at
Mon Aug 18 20:35:23 PDT 2014

On Mon, Aug 18, 2014 at 5:32 PM, Ian Hickson <ian at> wrote:

> On Mon, 18 Aug 2014, John Barton wrote:

>  > But in the case of image tags we already know exactly which image the
> > HTML depends upon.
> But other elements might depends on the <img>, and that we don't know.

> (For example, a graphical game might need some sprite assets to be loaded
> before it can start up. So its <script> might be marked as depending on an
> <img> element that loads that image. Or the script contents might have an
> import statement that refers to that image.)

Supporting this case seems straight-forward and can be done entirely by the
browser Loader implementation using hooks.

The reverse case, where a img depends on a script, is not a use case.

> > > Or indeed even when scripting is enabled, how would you use it to mark
> > > one non-loaded script as dependent on another non-loaded script such
> > > that when you later ask for the former, the latter loads
> > > automatically?
> >
> > import './latter';
> >
> > It's a solved problem for scripts.
> The key part of my question was "non-loaded". The "import" bit is in the
> script. The script isn't loaded yet, so we can't rely on it.

System.import('./former').then((former) => {
  // do stuff with former, knowing './former' imported './latter'.

Here we are expressing the dependency of the HTML file on the non-loaded
file './former' and it depends on the non-loaded file './loaded'.

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