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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
"use strict";
/* globals browser */
// By default, only the first handler for browser.runtime.onMessage which
// returns a value will get to return one. As such, we need to let them all
// receive the message, and all have a chance to return a response (with the
// first non-undefined result being the one that is ultimately returned).
// This way, about:compat and the shims library can both get a chance to
// process a message, and just return undefined if they wish to ignore it.
const onMessageFromTab = (function () {
const handlers = new Set();
browser.runtime.onMessage.addListener((msg, sender) => {
const promises = [...handlers.values()].map(fn => fn(msg, sender));
return Promise.allSettled(promises).then(results => {
for (const { reason, value } of results) {
if (reason) {
console.error(reason);
} else if (value !== undefined) {
return value;
}
}
return undefined;
});
});
return function (handler) {
handlers.add(handler);
};
})();