demoncord/src/api/settingsInj.js

// @flow

import webpack from "./webpack";

const settingsSym = Symbol("__settings");

// super secret value that shouldnt be exposed, used internally to avoid section conflicts and the like
const ovrwrtSctnSym: symbol = Symbol("__overwriteSection");

const settingsView = webpack.find(
    (m) => m.default && m.default.displayName === "SettingsView"
);

type getPredicateSectionsEntry =
    | {
          section: "HEADER",
          label: string,
      }
    | {
          section: "DIVIDER",
      }
    | {
          section: string,
          label: string,
          component: Function,
      };

function patch(args: mixed, ret: getPredicateSectionsEntry[]) {
    const processedEntries = window.demon[settingsSym].entries.map((e) => ({
        section:
            (e[ovrwrtSctnSym] ? e[ovrwrtSctnSym] : "DEMON_SETTINGS_LOADER_") +
            e.name,
        label: e.name,
        element: e.component,
    }));

    const injectionIndex =
        2 + ret.findIndex((section) => section.section === "Game Activity");
    ret.splice(
        injectionIndex,
        0,
        { section: "HEADER", label: "Demon" },
        ...processedEntries,
        { section: "DIVIDER" }
    );
    return ret;
}

function init() {
    window.demon[settingsSym] = {
        patch: window.demon.patcher.after(
            "getPredicateSections",
            settingsView.default.prototype,
            patch
        ),
        entries: [],
    };

    // debug
    window.demonunpatch = window.demon[settingsSym].patch;
}

function unInit(obj: Object) {
    window.demon[settingsSym].patch();
    delete window.demon[settingsSym];
}

function unregisterSettingsEntry(name: string) {
    let s = window.demon[settingsSym];
    s.entries = s.entries.filter(
        (e) => (e[ovrwrtSctnSym] ? e[ovrwrtSctnSym] : e.name) !== name
    );
}

function registerSettingsEntry(
    name: string,
    section: string,
    component: Function
): () => void {
    let entry: { [symbol | string]: any } = { name, component };
    if (section) entry[ovrwrtSctnSym] = section;
    window.demon[settingsSym].entries.push(entry);
    return () => unregisterSettingsEntry(name);
}

export default {
    init,
    unInit,
    registerSettingsEntry,
    unregisterSettingsEntry,
    ovrwrtSctnSymm: ovrwrtSctnSym,
};