message-queue/dispatcher.js

function Dispatcher() {
    this.hooks = [];
}

Dispatcher.prototype.hook = function(cb) {
    this.hooks.push(cb);
    return this.hooks.length-1;
};

Dispatcher.prototype.unhook = function(index) {
    this.hooks[index] = null;
};

Dispatcher.prototype.signal = function(value) {
    for(const cb of this.hooks) {
	if(cb) cb.apply(this, [value]);
    }
};

Dispatcher.prototype.clear = function() {
    this.hooks = [];
};

export default Dispatcher;