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docs(keyboard): clarify keyIsDown() documentation for key codes and browser compatibility #7806

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docs(keyboard): clarify keyIsDown() documentation for key codes and browser compatibility #7806

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49 changes: 31 additions & 18 deletions src/events/keyboard.js
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Original file line number Diff line number Diff line change
Expand Up @@ -807,25 +807,36 @@ p5.prototype._onblur = function(e) {
};

/**
* Returns `true` if the key it’s checking is pressed and `false` if not.
* Returns `true` if the key specified by `code` is currently pressed and `false`
* if not.
*
* `keyIsDown()` is helpful when checking for multiple different key presses.
* For example, `keyIsDown()` can be used to check if both `LEFT_ARROW` and
* `UP_ARROW` are pressed:
* `keyIsDown()` is helpful when checking for multiple different key presses
* simultaneously. For example, `keyIsDown()` can be used to check if both
* `LEFT_ARROW` and `UP_ARROW` are pressed:
*
* ```js
* if (keyIsDown(LEFT_ARROW) && keyIsDown(UP_ARROW)) {
* // Move diagonally.
* }
* ```
*
* `keyIsDown()` can check for key presses using
* <a href="#/p5/keyCode">keyCode</a> values, as in `keyIsDown(37)` or
* `keyIsDown(LEFT_ARROW)`. Key codes can be found on websites such as
* <a href="https://keycode.info" target="_blank">keycode.info</a>.
* `keyIsDown()` checks keys based on their
* <a href="https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/code" target="_blank">KeyboardEvent.code</a>
* or
* <a href="https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/key" target="_blank">KeyboardEvent.key</a>
* values. For example, `keyIsDown('ArrowLeft')` or `keyIsDown('a')` will return
* `true` if the left arrow key or the 'a' key are currently held down.
* p5.js constants such as `LEFT_ARROW` and `RIGHT_ARROW` can also be used.
* Note that due to browser inconsistencies, it is recommended to use key codes
* (like `LEFT_ARROW`) or `KeyboardEvent.code` strings instead of `KeyboardEvent.key`
* strings (like `'ArrowLeft'`) to ensure compatibility across different keyboard
* layouts and locales.
* You can find a list of key code values at
* <a href="https://developer.mozilla.org/en-US/docs/Web/API/UI_Events/Keyboard_event_code_values" target="_blank">keycode.info</a>.
*
* @method keyIsDown
* @param {Number} code key to check.
* @param {Constant|String} code The key to check, specified by its `KeyboardEvent.key`,
* `KeyboardEvent.code` value, or a p5.js constant.
* @return {Boolean} whether the key is down or not.
*
* @example
Expand All @@ -848,19 +859,19 @@ p5.prototype._onblur = function(e) {
*
* function draw() {
* // Update x and y if an arrow key is pressed.
* if (keyIsDown(LEFT_ARROW) === true) {
* if (keyIsDown(LEFT_ARROW)) {
* x -= 1;
* }
*
* if (keyIsDown(RIGHT_ARROW) === true) {
* if (keyIsDown(RIGHT_ARROW)) {
* x += 1;
* }
*
* if (keyIsDown(UP_ARROW) === true) {
* if (keyIsDown(UP_ARROW)) {
* y -= 1;
* }
*
* if (keyIsDown(DOWN_ARROW) === true) {
* if (keyIsDown(DOWN_ARROW)) {
* y += 1;
* }
*
Expand Down Expand Up @@ -891,20 +902,22 @@ p5.prototype._onblur = function(e) {
* }
*
* function draw() {
* // Update x and y if an arrow key is pressed.
* if (keyIsDown(37) === true) {
* // Update x and y if an arrow key or WASD is pressed.
* // Check using KeyboardEvent.code strings
* if (keyIsDown('ArrowLeft') || keyIsDown('KeyA')) {
* x -= 1;
* }
*
* if (keyIsDown(39) === true) {
* if (keyIsDown('ArrowRight') || keyIsDown('KeyD')) {
* x += 1;
* }
*
* if (keyIsDown(38) === true) {
* // Check using KeyboardEvent.key strings
* if (keyIsDown('ArrowUp') || keyIsDown('w')) {
* y -= 1;
* }
*
* if (keyIsDown(40) === true) {
* if (keyIsDown('ArrowDown') || keyIsDown('s')) {
* y += 1;
* }
*
Expand Down