gitbook/theme/javascript/core/state.js

define([
    "jQuery"
], function() {
    var $book = $(".book");

    return {
        '$book': $book,

        'githubId': $book.data("github"),
        'level': $book.data("level"),
        'basePath': $book.data("basepath"),
        'revision': $book.data("revision")
    };
});