Source: jsdoc/Rectangle.js

/**
 * A Rectangle defined a rectangle by left,top,right,bottom coordinates
 * @typedef {Integer[]} Rectangle
 * @property {Integer} [0] The x-coordinate of the left
 * @property {Integer} [1] The y-coordinate of the top
 * @property {Integer} [2] The x-coordinate of the right
 * @property {Integer} [3] The y-coordinate of the bottom
 */