Cloud Functions: what is the difference between exports.function = vs export const function =?

Question

This is going to be a very elementary question but I want to have a clear understanding of the difference between exports.function = vs export const function = inside index.ts of functions folder generated from Firebase Cloud Functions.

  exports.function = functions
      .runWith(CONFIG.MEMORY)
      .https.onRequest(async (req, res) => {
      console.log("hi")
  })
  
  export const function = functions
      .runWith(CONFIG.MEMORY)
      .https.onRequest(async (req, res) => {
      console.log("hi")
  })

I understand both totally work fine, but for what reason is it considered to be better to use exports.function = than export const function inside index file at the top level of functions folder?

I read this `export const` vs. `export default` in ES6

If it’s not at the top level of folder, I can understand their behaviors but what I want to know is how firebase cloud functions deal with export const function differently than exports.function when it’s at the top level of functions folder, which is at index file???