Js 职责链模式 简单理解

function Handler(s) {
    this.successor = s || null;
    this.handle = function () {
        if (this.successor) {
            this.successor.handle();
        }
    }
}

var app = new Handler({
    handle: function () {
        console.log(‘app handle‘);
    }
});

var dialog = new Handler(app);
dialog.handle = function () {
    console.log(‘dialog before ...‘);
    app.handle(this);
    console.log(‘dialog after ...‘);
};
var button = new Handler(dialog);
button.handle = function () {
    console.log(‘button before ...‘);
    dialog.handle(this);
    console.log(‘button after ...‘);
};
 
button.handle();