JPM [error] Message: SyntaxError: duplicate label

问题

I'm working on a firefox extension and am getting this error message. What does it mean?

The only label I have is from:

require("sdk/ui/button/action").ActionButton({
    id: "show-popup",
    label: "something that can't possibly be a duplicate",
    ...

Later on I add a background page:

require("sdk/page-worker").Page({
    contentScript: [ ... some scripts ... ]
});

While testing, I get the error:

> jpm run -b $(which firefox)
JPM [info] Starting jpm run on MyExtensionTitle
JPM [info] Creating a new profile
console.error: myextensiontitle: 
JPM [error]   Message: SyntaxError: duplicate label

This only happens when I add the background script. How can I debug further? All I have to go on is an ambiguous terminal message and no line number.

回答1:

A page-worker's contentScript is the source code. It should be contentScriptFile instead:

require("sdk/page-worker").Page({
    contentScriptFile: [ ... some scripts ... ]
});

来源：https://stackoverflow.com/questions/35029914/jpm-error-message-syntaxerror-duplicate-label