The Drive API offers a whole range of conversions between mimeTypes, but it’s a little fiddly to figure out exactly how. This library takes a file and an a desired output format and converts it for you. Sometimes, there’s not a direct route – for example if you need to convert a word file to a pdf, it first needs to get converted to a Google Doc, then to a Pdf. This library automatically works out and actions any intermediate conversions required.
The Drive API offers a whole range of conversions between mimeTypes, but it’s a little fiddly to figure out exactly how. This library takes a file and an a desired output format and converts it for you. Sometimes, there’s not a direct route – for example if you need to convert a word file to a pdf, it first needs to get converted to a Google Doc, then to a Pdf. This library automatically works out and actions any intermediate conversions required.
Article link - https://ramblings.mcpher.com/gassnippets2/apps-script-file-conversions/