What's up with "import declarations may only appear at top level of a module"

[Kent Williams]

So SpiderMonkey 52 supports ES6, and we're embedding the TypeScript
compiler.  I got that part working but I get an error compiling the
compiled scripts.

"compilation exception: import declarations may only appear at top level
of a module: file: , line: 1"

This is my test program:

import Add from "./TSTest2";
let x:string='Hello from Typscript\n';

print_doc(x + Add(2,2).toString() + '\n');
// cause_an_error;

And this is the module it's trying to import:

export default function Add(x: number, y:number): number {
     return x + y;
}

When I google that error message, all the references to <script> tags in
client side JS.  How do I get a server-side SpiderMonkey interpreter to
not throw that error.

[Miles]

Sorry, I don't know the answer to this, but I would be very interested to find out if you manage to get it to work. I'm trying to upgrade our Spidermonkey embedding from 1.8.5 and I have grabbed version 59. I'm very interested to know if/how ES6 features are enabled. Are they by default or do you have to call some functions etc.
If you find the solution please can you post. Many thanks.

[Jan de Mooij]

You're probably trying to compile/execute the script as a plain script
instead of a module. See JS::CompileModule. There's also support for
modules in the JS shell (-m module I think), you could look at that as well.

Also, you might want to consider upgrading to ESR 60, its module support is
likely a lot better than what's in 52.

Hope this helps,
Jan

On Tue, Jun 12, 2018 at 3:05 PM, Kent Williams <kwil...@leepfrog.com>
wrote:

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[Kent Williams]

OH and there's nothing about CompileModule in the SpiderMonkey API
documentation.

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[Kent Williams]

There's a simple issue: Scripts with anything related to modules require
using JS::CompileModule. Regular JS scripts require using JS::CompileScript

I got onto the #JSAPI IRC channel and with the help of those people I
was able to build something that works.

You're using a newer version of SpiderMonkey than I targeted, so you may
have to do some tweaks.  If you get it working please submit a pull
request to me that shows your changes.

https://github.com/Chaircrusher/SpiderMonkeyES6Example

You've (yet again) become a victim of Mozilla's spotty commitment to
documentation.  I would respectfully submit that having "Ask the actual
developers on IRC" as a documentation strategy is frustrating and flawed.

On 06/13/2018 03:58 AM, Miles wrote:
> Sorry, I don't know the answer to this, but I would be very interested to find out if you manage to get it to work. I'm trying to upgrade our Spidermonkey embedding from 1.8.5 and I have grabbed version 59. I'm very interested to know if/how ES6 features are enabled. Are they by default or do you have to call some functions etc.
> If you find the solution please can you post. Many thanks.

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> dev-tech-js-engine mailing list
> dev-tech-...@lists.mozilla.org

> https://lists.mozilla.org/listinfo/dev-tech-js-engine