JavaScript Loader

Loaders are transformations that are applied to the source code of a module or a script. They allow you to pre-process files or html with javascript inside as you import or “load” them. Thus, loaders are kind of like “tasks” in other build tools and provide a powerful way to handle front-end build steps.
The idea is to download a JS programm and run it native locally in a runtime browser (webview2) with some modifications in it, based on a script you deliver before. I call this a multiple deployment as a fixture:

const
  SINWAVES2URL= 'https://raw.githack.com/maxkleiner/maXbox4/master/assets/sinwavesjs.html';
aMS:= TMemoryStream.Create;
 try
   HttpGet(SINWAVES2URL, amS)
   writeln('urlcontent size: '+itoa((ams.size)));
   aMS.Seek(0, 0);
   memoHTML.lines.loadfromstream(aMs);
   //javascript fixture_
   memoHTML.text:= StringReplace(memoHtml.text,'frequency = 20;','frequency = 30;',[rfReplaceAll]); 
   memoHTML.text:= StringReplace(memoHtml.text,'Sine Wave</h3>','Sine Wave F30</h3>',[rfReplaceAll]); 
   navigatetoString(memoHTML.text);
 finally
   aMS.Free
 end; 

For example, you can use loaders to tell a website to load a CSS with javascript file and to modify parameters in JavaScript before you run it in a local browser webview2.

Loaders can be chained. Each loader in the chain applies transformations to the processed resource for example load the url as a stream in a memo with lines, modify two parameters (frequency and title in our example) an run it with navigatetoString(memoHTML.text); on a browser:

with TEdgeViewForm.create(self) do begin
   PageControl1.ActivePageIndex := 1;
   edit1.text:= SINWAVES2URL;
   aMS:= TMemoryStream.Create;
   try
     HttpGet(SINWAVES2URL, amS)
     writeln('urlcontent size: '+itoa((ams.size)));
     aMS.Seek(0, 0);
     memoHTML.lines.loadfromstream(aMs);
     //javascript fixture_
     memoHTML.text:= StringReplace(memoHtml.text,'frequency = 20;','frequency = 30;',[rfReplaceAll]); 
     memoHTML.text:= StringReplace(memoHtml.text,'Sine Wave</h3>','Sine Wave F30</h3>',[rfReplaceAll]); 
     navigatetoString(memoHTML.text);
   finally
     aMS.Free
   end;    
   showmodal
   free;
 end;  

The above is the detailed content of JavaScript Loader. For more information, please follow other related articles on the PHP Chinese website!