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Full Stack JavaScript Techdegree Student 161 PointsQuestion on the event listener on app.js
Hello,
With the event listerner which Listens for click on #begin-game
and calls startGame() on game object. When I use arrow function for the event listener, I get a TypeError that 'this' is undefined
const game = new Game();
/**
* Listens for click on `#begin-game` and calls startGame() on game object
*/
document.getElementById('begin-game').addEventListener('click', () => {
game.startGame();
this.style.display = 'none';
document.getElementById('play-area').style.opacity = '1';
});
BUT when I use the function keyword it works. Please is there any explanation behind this?
const game = new Game();
/**
* Listens for click on `#begin-game` and calls startGame() on game object
*/
document.getElementById('begin-game').addEventListener('click', function(){
game.startGame();
this.style.display = 'none';
document.getElementById('play-area').style.opacity = '1';
});
2 Answers
Martin Zarate
10,723 PointsHere is an explanation on how arrow function binds to "this" https://codeburst.io/javascript-arrow-functions-for-beginners-926947fc0cdc Change "this" to the object itself "document.getElementById('begin-game')" it will work.
ada harrison
Full Stack JavaScript Techdegree Student 161 PointsThanks very much
Dave StSomeWhere
19,870 PointsDave StSomeWhere
19,870 PointsHere's the MDN Explanation