ES6导出时意外的令牌

Question

I'm trying to understand how ES6 export works.

Here are two local files:

main.html :

<script src="module.js"></script>
<script>
    import {hello} from './module'; // Tried both "module" and "module.js"
    let val = hello();
    alert(val);
</script>

module.js :

export function hello() {
    return 'Hello';
}

Expected result: alert with "Hello" text in it. Actual result: errors:

module.js - line 1: Unexpected token export

main.html - line 3: Unexpected token {

How to make it work?

PS. Tested in Chrome 67.

Answer 1

Full support of JavaScript modules have been added to Chrome since version 61 . Here's the essential part you apparently missed in the doc:

Modules must be eventually included in your HTML with type="module" , which can appear as an inline or external script tag.

You don't have to use the first script; import will direct browser to download the required module. So this should be enough:

<script type="module">
    import {hello} from './module.js';
    let val = hello();
    alert(val);
</script>

There's a caveat, however: you won't be able to serve modules from filesystem directly in Chrome - you'll need to either set up a 'regular' HTTP server or apply workarounds described in this thread .