@ledgerhq/hw-transport-node-hid/lib-es/listenDevices.js

Ledger Hardware Wallet Node implementation of the communication layer, using node-hid

import EventEmitter from "events";
import { usb } from "usb";
import debounce from "lodash/debounce";
import { getDevices } from "@ledgerhq/hw-transport-node-hid-noevents";
import { log } from "@ledgerhq/logs";
export default (delay, listenDevicesPollingSkip) => {
    const events = new EventEmitter();
    events.setMaxListeners(0);
    let listDevices = getDevices();
    const flatDevice = d => d.path;
    const getFlatDevices = () => [...new Set(getDevices().map(d => flatDevice(d)))];
    const getDeviceByPaths = paths => listDevices.find(d => paths.includes(flatDevice(d)));
    let lastDevices = getFlatDevices();
    const poll = () => {
        if (!listenDevicesPollingSkip()) {
            log("hid-listen", "Polling for added or removed devices");
            let changeFound = false;
            const currentDevices = getFlatDevices();
            const newDevices = currentDevices.filter(d => !lastDevices.includes(d));
            if (newDevices.length > 0) {
                log("hid-listen", "New device found:", newDevices);
                listDevices = getDevices();
                events.emit("add", getDeviceByPaths(newDevices));
                changeFound = true;
            }
            else {
                log("hid-listen", "No new device found");
            }
            const removeDevices = lastDevices.filter(d => !currentDevices.includes(d));
            if (removeDevices.length > 0) {
                log("hid-listen", "Removed device found:", removeDevices);
                events.emit("remove", getDeviceByPaths(removeDevices));
                listDevices = listDevices.filter(d => !removeDevices.includes(flatDevice(d)));
                changeFound = true;
            }
            else {
                log("hid-listen", "No removed device found");
            }
            if (changeFound) {
                lastDevices = currentDevices;
            }
        }
        else {
            log("hid-listen", "Polling skipped, re-debouncing");
            debouncedPoll();
        }
    };
    const debouncedPoll = debounce(poll, delay);
    const attachDetected = device => {
        log("hid-listen", "Device add detected:", device);
        debouncedPoll();
    };
    usb.on("attach", attachDetected);
    log("hid-listen", "attach listener added");
    const detachDetected = device => {
        log("hid-listen", "Device removal detected:", device);
        debouncedPoll();
    };
    usb.on("detach", detachDetected);
    log("hid-listen", "detach listener added");
    return {
        stop: () => {
            log("hid-listen", "Stop received, removing listeners and cancelling pending debounced polls");
            debouncedPoll.cancel();
            usb.removeListener("attach", attachDetected);
            usb.removeListener("detach", detachDetected);
        },
        events,
    };
};
//# sourceMappingURL=listenDevices.js.map