ES6 import module inside node execution script

Question

I'm trying to execute a node script inside package.json which looks like this.

"parse-xlsx": "node ./services/orders-parsing/xlsx-parser executeXlsxParsing ./private/testdata/$FILENAME"

So when I run FILENAME=unfried-xlsx-2.xlsx npm run parse-xlsx for exemple, it executes this:

import XlsxParser from "./executeExcelParsing";

const executeXlsxParsing = () => {

   const xlsxParser = new XlsxParser({ fileName: process.argv.slice(2)[1] })

   xlsxParser.executeParsing()
}

export default executeXlsxParsing;

But when I do so, I got this error

SyntaxError: Cannot use import statement outside a module

I did try to flag with --input-type but did not work and it outputs the same error than the one above:

"parse-xlsx": "node --input-type=module ./services/orders-parsing/xlsx-parser executeXlsxParsing ./private/testdata/$FILENAME"

For some reason I don't want to use type=module inside my package.json file.

Any workaround to be able to "force" the execution of this script with ES6 imports? Did try with latest LTS node 16.17.0 and my "old" version v12.22.1.

Thanks !

Answer 1

node --input-type only tells node how to parse string input you're passing it:

> node --help
Usage: node [options] [ script.js ] [arguments]
       node inspect [options] [ script.js | host:port ] [arguments]

Options:
  ...

  --input-type=...      set module type for string input

  ...

However, you're telling it to run the file ./services/orders-parsing/xlsx-parser so that won't work.

Your only option (until Node changes how --input-type works) is to have a package.json with the type property set to module . Thankfully, you canhave lots of package.json files, and node will simply use the one closest to the file it's being asked to run, so you can add a minimal package.json inside your services/orders-parsing dir, and then make sure that's set to "type": "module" , and now Node will run in ESM mode when asked to run files in the services/orders-parsing dir.

However, also note that if you want to pass arguments to xlsx-parser , you will need to use:

"parse-xlsx": "node ./services/orders-parsing/xlsx-parser -- executeXlsxParsing ./private/testdata/$FILENAME"

with those explicit -- in there, because:

> node --help
Usage: node [options] [ script.js ] [arguments]
       node inspect [options] [ script.js | host:port ] [arguments]

Options:
  -                     script read from stdin (default if no file name is
                        provided, interactive mode if a tty)
  --                    indicate the end of node options

If you don't add those -- then everything is considered options for the node executable instead of for whatever script you're running.