FileSystemEntry.fullPath
 The read-only fullPath property of the FileSystemEntry interface returns a USVString specifying the full, absolute path from the file system's root to the file represented by the entry. 
This can also be thought of as a path which is relative to the root directory, with a "/" prepended to it to make it absolute.
Syntax
var fullPath = FileSystemEntry.fullPath;
Value
A USVString indicating the entry's full path.
Example
 This example shows a function which is called with a file system; it then gets a FileSystemFileEntry for a file named data.json and returns its full path. 
function gotFileSystem(fs) { let path = ""; fs.root.getFile("data.json", { create: true, exclusive: true }, function(entry) { path = fullPath; }, handleError(error)); return path; }
 Obviously, this is somewhat contrived, since we know that the file's full path is "/data.json", having just looked it up ourselves, but the concept holds up for scenarios in which you don't know it. 
Specifications
Browser compatibility
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
| fullPath | 8 | 79 | 50 | No | No | 11.1 | ≤37 | 18 | 50 | No | 11.3 | 1.0 | 
See also
    © 2005–2021 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
    https://developer.mozilla.org/en-US/docs/Web/API/FileSystemEntry/fullPath