JavaScript/TypeScript plugin pipeline

gistfile1.js

function plugin1(context, next) {
    console.log('plugin1');
    console.log(context.event);
    next();
}

function plugin2(context, next) {
    console.log('plugin2');
    someIO(next);
}

function plugin3(context, next) {
    console.log('plugin3');
    context.refid = '123';
    next();
}

function badplugin(context, next) {
    throw new Error('Blake');
}

function someIO(next) {
    console.log('IO');
    next();
}

var util = util || {};
util.CallChain = function() {
    var cs = [];
    this.add = function(call) {
        if (call)
            cs.push(call);
    };
    this.execute = function(context) {
        var wrap = function (call, next) {
            return function () {
                try {
                    call(context, next);
                } catch (ex) {
                    // log to the exceptionless client logger
                    console.log(ex);
                }
            };
        };
        for (var i = cs.length-1; i > -1; i--) {
            cs[i] = 
                wrap(
                    cs[i], 
                    i < cs.length - 1 
                        ? cs[i + 1] 
                        : null);
        }
        cs[0]();
    };
};

var chain = new util.CallChain();
chain.add(plugin1);
chain.add(null);
chain.add(plugin2);
chain.add(plugin3);
//chain.add(badplugin);
chain.add(function(context, next) {
    console.log('enqueue event');
    console.log(context.event);
    if (next) next();
});

var ctx = { 'event': { 'stuff': 'hi' } };
chain.execute(ctx);
console.log('done');
console.log(ctx);

gistfile2.ts

export class Pipeline<Type, Context> {
  private _actions = [];
 
  public add(action:(context:Context, next?:() => void) => void): void {
    if (action) {
      this._actions.push(action);
    }
  }
 
  public run(context:Context): void {
    var wrap = function (action:(context:Context, next?:() => void) => void, next?:() => void) {
      return function () {
        try {
          action(context, next);
        } catch (ex) {
          console.log(ex);
        }
      };
    };
 
    for (var index = this._actions.length - 1; index > -1; index--) {
      this._actions[index] = wrap(
        this._actions[index],
        index < this._actions.length - 1 ? this._actions[index + 1] : null
      );
    }
 
    this._actions[0]();
  }