get_global_object.js

/**
 * Returns the global object.
 * Works even inside ES6 modules.
 */
function getGlobalObject() {
    // Workers don’t have `window`, only `self`
    if (typeof self !== 'undefined') {
        return self;
    }
    if (typeof global !== 'undefined') {
        return global;
    }
    // Not all environments allow eval and Function
    // Use only as a last resort:
    return new Function('return this')();
}

Didn't know that browsers have a window.self property which returns window, neat trick.