TypeError: _my_lib.default is not a function

import { gen_index_of } from “./components/lib/my.lib”;
一定要加{},如果写成
import gen_index_of from “./components/lib/my.lib”;
会报错:
TypeError: _my_lib.default is not a function

my_lib.js

export function shuffle(arr) {
let i = arr.length;
while (i) {
let j = Math.floor(Math.random() * i--);
[arr[j], arr[i]] = [arr[i], arr[j]];
}
}

export function gen_index_of(arr) {
var index_of = {};
for (let i = 0; i < arr.length; ++i) {
index_of[arr[i]] = i;
}
return index_of;
}

export function shallow_copy_array(arr) {
var ret = [];
for (let v of arr) {
ret.push(v);
}
return ret;
}