javascript - Better to export an object containing function, or just export multiple functions in ES6 (Is there a convention?)

Question

This is a question of convention. I'm new to ES6 but I'm trying to make use of the module system. Is preferred/more common to export multiple functions from a single file, or export a single object containing these functions.

Example:

utils.js

export function add(num1, num2) {
  return num1 + num2;
}

export function minus(num1, num2) {
  return num1 - num2;
}

and use it like this:

import {add, minus} from 'utils.js';

vs

utils.js

const utils = {
  add: (num1, num2) => {
    return num1 + num2;
  },

  minus: (num1, num2) => {
    return num1 - num2;
  }
}

export default utils;

In a utils file that contains a 50-100 functions, it seems the second way would be the clear winner. But there's just something that feels wrong about it to me, and I don't know why.

Answer 1

Going forward, it's probably better to export multiple functions, as tree shaking allows module bundlers to eliminate dead code based on whether it's been imported or not.

If you export one large object, it's not always possible to use static analysis to tell which functions need to be kept and which can be safely discarded.

If you export multiple named functions, then the module bundler can analyze the AST then safely whitelist the functions which you are actually importing.