Perform action before file upload

[mastarenee]

Is it possible that after the user has selected an image I can call an (onBeforeUpload) function to run edits on the image using ng2-pica. If not can I remove the URL so the file doesn't upload but then after I've performed my edits get your plugin to make a call to the server with a URL I would provide it with?

[shangab]

This is very important @mastarenee , for example I have a one PHP back end file to handle uploads of different types of images (Cars, students, ...ect). I want to stash other POST prams to be used in my back end PHP? what can I do?? a call back such as:

OnBeforeUpload ($params){
      $params.push({type:xyz, folder:abc...etc});
}

is very important

[UncleDave]

How does the following signature sound:

onBeforeUpload: (files: FileList) => boolean | FileList | Promise<boolean> | Promise<FileList>

onBeforeUpload will be called when images are selected/dropped, the list of files will be passed into this function. Return a boolean or a promise that resolves to a boolean to continue (true) or abort (false). Alternatively return a modified FileList (or promise) containing the files to continue with.

Or perhaps the return value of the function could be an object with more things in it, if there's a requirement:

{
  files: FileList,
  queryParams: Map<string, string>,
  url: string
}