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JavaScript Object-Oriented JavaScript: Challenge Making the Game Interactive playToken() Method Solution

playToken, moveLeft and moveRight methods

I had to tweak the moveLeft and moveRight methods a bit to get them to work. The .style.left property does not seem to accept numeric values for some reason.

  moveLeft() {
    if (this.columnLocation > 0) {
      this.htmlToken.style.left = `${this.offsetLeft - 76}px`;
      this.columnLocation -= 1;

  moveRight(columns) {
    if (this.columnLocation < columns - 1) {
      this.htmlToken.style.left = `${this.offsetLeft + 76}px`;
      this.columnLocation += 1;

Note: I had to assign this.htmlToken.style.left a string value for example "195px" instead of 195 as a numeric value as shown in the video.

Does anyone know what is going on here?

Thank you so much! I was running into the same thing. left and right wasn't working. I kept thinking "isn't it supposed to have px on the end." Idk how many times I re-watched the video trying to find where my code differed.

Makes me wonder how her token was even able to move in the video....

2 Answers

Steven Parker
Steven Parker
218,812 Points

I think you may have discovered a bug in the course! I believe style properties are always strings, plus there's the added factor of needing to specify a unit (such as "px") for any value other than 0.

You may want to make a bug report to the Support department. And we can try tagging Ashley Boucher in case she would like to comment directly.

Elliott LaJoie
Elliott LaJoie
14,769 Points

This is exactly what I needed! I haven't brushed up on my css in awhile so I appreciate that!

Alex Franklin
Alex Franklin
12,398 Points

how did you get the play token / drop to work on keyDown - I am now stuck trying to figure that out... ANY ANSWERS??

This is the code that plays and drops the token. I don't know if it is different from the original though. I hope this helps:

playToken() method in the Game.js file:

   * find space object to drop token into; drop token
  playToken() {
    const spaces = this.board.spaces;
    const activeToken = this.activePlayer.activeToken;
    const targetColumn = spaces[activeToken.columnLocation];
    let targetSpace = null;

    for (let space of targetColumn) {
      if (space.token === null) {
        targetSpace = space;

    if (targetSpace !== null) {
      console.log('token played');
      game.ready = false;
      // second argument is a callback function, the callback function is
      // executed when the .drop function has finished.
      activeToken.drop(targetSpace, () => {
        game.updateGameState(activeToken, targetSpace);
      console.log('token dropped');

drop() method in the Token.js file:

   * Drops html token into targeted board space.
   * @param   {Object}    target  - Targeted space for dropped token.
   * @param   {function}  reset   - function to call after animation is complete
  drop(target, reset) {
    this.dropped = true;

      top: (target.y * target.diameter)
    }, 750, 'easeOutBounce', reset);