mami/src/mami.js/compat.js

const MamiCompat = (path, handler) => {
    if(typeof path !== 'string')
        throw 'path must be a string';
    if(typeof handler !== 'object')
        throw 'handler must be a property definition';

    path = path.split('.');

    const final = path.pop();
    if(final === undefined)
        throw 'invalid path';

    let current = window;
    for(const part of path) {
        if(!(part in current))
            current[part] = {};
        current = current[part];
    }

    if(!(final in current))
        Object.defineProperty(current, final, handler);
};