woocommerce-paypal-payments/modules/ppcp-button/resources/js/modules/ButtonModuleWatcher.js

class ButtonModuleWatcher {

    constructor() {
        this.contextBootstrapRegistry = {};
        this.contextBootstrapWatchers = [];
    }

    watchContextBootstrap(callable) {
        console.log('ButtonModuleWatcher.js: watchContextBootstrap', this.contextBootstrapRegistry)
        this.contextBootstrapWatchers.push(callable);
        Object.values(this.contextBootstrapRegistry).forEach(callable);
    }

    registerContextBootstrap(context, handler) {
        this.contextBootstrapRegistry[context] = {
            context: context,
            handler: handler
        }

        // Call registered watchers
        for (const callable of this.contextBootstrapWatchers) {
            callable(this.contextBootstrapRegistry[context]);
        }
    }

}

window.ppcpResources = window.ppcpResources || {};
const buttonModuleWatcher = window.ppcpResources['ButtonModuleWatcher'] = window.ppcpResources['ButtonModuleWatcher'] || new ButtonModuleWatcher();

export default buttonModuleWatcher;