annotated.js

/* eslint-disable */

k = 13,                         // initial paddle position
x =                             // ball position
W = 27,                         // board width
X = Y = 1;                      // ball x and y direction
setInterval(function() {

  for (
    i =                         // iterator
    h = "",                     // output string

    k = k < 0 ? 0 :             // keep paddle in bounds
      24 < k ? 24 :
      k,

    X = x % W ?                 // reflect if ball hits wall
      X :
      -X,

    Y =                         // change Y direction
      x < 0 ? 1 :               // reflect if ball hit top border
        297 < x ? (             // if ball hits bottom border ...
          1 % (
            x - 299 - k         // calculate distance to paddle center
          ) ?                   // if distance is not 0, 1, -1
            p :                 // ... break the game
            -1                  // otherwise reflect up
      ) : Y,

    x += Y * (W + X * Y);       // update ball position based on direction

    i++ < 297 + k;              // draw field and paddle offset

    p.innerHTML = h + 888       // draw paddle
  )
    h +=                        // draw character
      i % W ?                   // if in bounds ...
        i ^ x ? " " : 0 :       // ... draw ball or space
      "|\n";                    // else draw border and break line

}, 99)                          // render loop