I have a large set of polygons in shp, each with unique string value in attribute table. Now I need each of them in separate `.geojson` file (one polygon = one .geojson) but with name equal to the value in table.

I've found <i>Multipart to singleparts</i> in default processing panel which works just fine with the iterate option enabled, but there's no way to choose name from table. I have never wrote a script for qgis but I have some basic knowledge of programming and editing code so I tried to find this script on the computer and modify it. However I can't locate the file by name.

Or maybe there is another option to write script using this ready piece? Or some plugin which allows saving to multiple files with chosen filename?

I'm using QGIS 2.18 and QGIS 3.0.