Meal Maker TypeError: Cannot read property 'push' of undefined


I am new here, trying to navigate through the mysteries of JavaScript. So far so good until this Meal Maker project where I got this error that I cannot fix. I read some of the previous posts with the same title but couldn’t figure it out.
Could anyone please give me a hand ?
Thank you in advance.

return this._courses[courseName].push(dish);

TypeError: Cannot read property ‘push’ of undefined
at Object.addDishToCourse (/home/ccuser/workspace/learn-javascript-objects-meal-maker/app.js:40:37)
at Object. (/home/ccuser/workspace/learn-javascript-objects-meal-maker/app.js:58:6)
at Module._compile (module.js:571:32)
at Object.Module._extensions…js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)
at Function.Module._load (module.js:439:3)
at Module.runMain (module.js:605:10)
at run (bootstrap_node.js:427:7)
at startup (bootstrap_node.js:151:9)

This question keeps popping up, surprised none of the other topics helped. Well, lets find out what is causing the undefined:

    console.log(this._courses, courseName);
    return this._courses[courseName].push(dish);

i can see your courses object doesn’t have an appetizer key. See the problem?

Yeap, thanks for pointing out. A new day, a new fresh look and the mistake was spotted.