### Start Stockfish.js Web Server

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/README.md

Run this command in the repository root to start the local web server for accessing web examples.

```bash
node server.js
```

--------------------------------

### Install Stockfish.js Globally

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/README.md

Install the stockfish.js package globally for command-line usage.

```bash
npm install -g stockfish
```

--------------------------------

### Setup Sample Commands for Select Box

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Populates a select box with sample Stockfish.js commands for easy selection and execution. Handles command selection and sends the chosen command to the engine.

```javascript
var selectBox = document.createElement("select");
var commands = ["setoption name Skill Level value 20", "setoption name Skill Level value 10", "setoption name Skill Level value 0", "setoption name Contempt value 0", "setoption name Contempt value 50", "setoption name Contempt value 100", "setoption name NalimovCache value 0", "setoption name NalimovCache value 1", "setoption name NalimovCache value 2", "setoption name NalimovCache value 3", "setoption name NalimovCache value 4", "setoption name MultiPV value 1", "setoption name MultiPV value 3", "setoption name Clear Hash", "setoption name Clear Hash;ucinewgame", "go movetime 1000", "go wtime 2000 btime 2000", "go nodes 30000", "go ponder", "ponderhit"];
commands.forEach(function (cmd) { var el = document.createElement("option"); el.value = el.textContent = cmd; selectBox.appendChild(el); });
selectBox.selectedIndex = -1;
selectBox.oninput = function () { if (selectBox.value) { sendCommand(selectBox.value); selectBox.selectedIndex = -1; } };
```

--------------------------------

### Get Configuration from Local Storage

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Retrieves a configuration value from local storage by key. Returns a default value if the key is not found or parsing fails.

```javascript
function getConfig(key, defaultVal) {
  var val;
  try {
    val = localStorage.getItem(key);
    if (val !== null && typeof val !== "undefined") {
      return JSON.parse(val);
    }
  } catch (e) {}
  return defaultVal;
}
```

--------------------------------

### Move Cursor to End of Input Element

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Sets the selection start and end points of an input element to its value's length, effectively moving the cursor to the end. Uses setTimeout to ensure it runs after the current execution context.

```javascript
function cursorToEnd(el) {
  setTimeout(function () {
    el.selectionStart = el.selectionEnd = el.value.length;
  }, 1);
}
```

--------------------------------

### Populate Sample Commands Dropdown

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Populates a select box with predefined sample chess engine commands.

```javascript
function setupSamples() {
  var selectBox = document.getElementById("selection");
  [ "go", "stop", "uci", "isready", "ucinewgame", "go depth 10", "go depth 20", "go depth 25", //"bench", "d", "eval", "go;sleep(stop,1000)", "position startpos", "position fen r1k4r/ppp1bq1p/2n1N3/6B1/3p2Q1/8/PPP2PPP/R5K1 w - - 0 1;d", "position fen 8/7p/6p1/5p2/Q4P2/2p3P1/3r3P/2K1k3 w - - 2 44 moves a4a7;d", "setoption name Threads value 1", "setoption name Threads va
```

--------------------------------

### Initialize Stockfish.js Game

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/demo.html

Initializes a new chess game with Stockfish.js. Sets up game parameters like base time, increment, skill level, and player color. This function should be called after the Stockfish engine is ready.

```javascript
var wait_for_script;
var newGame = function (){};

function init() {
  var game = engineGame();
  newGame = function newGame() {
    var baseTime = parseFloat($('#timeBase').val()) * 60;
    var inc = parseFloat($('#timeInc').val());
    var skill = parseInt($('#skillLevel').val());
    game.reset();
    game.setTime(baseTime, inc);
    game.setSkillLevel(skill);
    game.setPlayerColor($('#color-white').hasClass('active') ? 'white' : 'black');
    game.setDisplayScore($('#showScore').is(':checked'));
    game.start();
  }
  game.setSkillLevel
  document.getElementById("skillLevel").addEventListener("change", function () {
    game.setSkillLevel(parseInt(this.value, 10));
  });
  newGame();
}

/// If we load Stockfish.js via a <script> tag, we need to wait until it loads.
if (!wait_for_script) {
  document.addEventListener("DOMContentLoaded", init);
}
```

--------------------------------

### Initialize Stockfish.js in Node.js

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/README.md

This script demonstrates how to require and use stockfish.js as a CommonJS module in Node.js. It initializes the engine and sets up a listener for engine output.

```javascript
var stockfish = require("stockfish")("lite-single", function onReady() {
    stockfish.sendCommand("uci");
    stockfish.sendCommand("go depth 5");
});
stockfish.listener = function (line) {
    console.log("STDOUT:", line);
    if (/bestmove \S+/.test(line)) {
        console.log("The best move is " + line.match(/bestmove (\S+)/)[1] + ".");
    }
};
```

--------------------------------

### Set Configuration in Local Storage

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Saves a configuration value to local storage by key. Uses JSON.stringify to serialize the value.

```javascript
function setConfig(key, value) {
  try {
    return localStorage.setItem(key, JSON.stringify(value));
  } catch (e) {}
}
```

--------------------------------

### Set Temporary Command for Input

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Stores the current input value in a temporary variable and saves it to local storage.

```javascript
function setTmpCmd(val) {
  tmpCmd = val;
  setConfig("tmpCmd", val);
}
```

--------------------------------

### Send Command to Stockfish.js Engine

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Sends a command to the Stockfish.js engine. Supports multiple commands separated by semicolons and delayed commands using a 'sleep(CMD, DELAY_MS)' syntax.

```javascript
function sendCommand(cmd, skipSave) {
  var match;
  cmd = cmd.trim();
  if (cmd) {
    /// Supports multiple commands separated by semicolons
    if (cmd.indexOf(";") > -1) {
      cmd.split(";").forEach(function (part) {
        sendCommand(part, true);
      });
    } else {
      writeOutput(" > " + cmd);
      /// Supports delayed commands by wrapping in a sleep function, like setTimeout: sleep(CMD, DELAY_MS)
      match = cmd.match(/^sleep\(\s*(.+)\s*,\s*(\d+)\s*\)$/);
      if (match) {
        setTimeout(function () {
          sendCommand(match[1], true);
        }, Number(match[2]));
      } else {
        engine.send(cmd);
      }
    }
    if (!skipSave) {
      lastCmds.push(cmd);
      removeDupsRev(lastCmds);
      if (lastCmds.length > 100) {
        lastCmds = lastCmds.slice(-80);
      }
      setConfig("lastCmds", lastCmds);
      lastCmdsIndex = lastCmds.length;
    }
  }
}
```

--------------------------------

### Handle Input Keydown Events

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Manages keydown events for the input field, including sending commands on Enter, navigating command history with ArrowUp/ArrowDown, and managing temporary command storage.

```javascript
input.onkeydown = function keypress(e) {
  if (e.key === "Enter") {
    sendCommand(input.value);
    input.value = "";
    setTmpCmd("");
  } else if (e.key === "ArrowUp") {
    if (lastCmdsIndex > 0) {
      if (lastCmdsIndex === lastCmds.length) {
        setTmpCmd(input.value);
      }
      --lastCmdsIndex;
      input.value = lastCmds[lastCmdsIndex];
      cursorToEnd(input);
    }
  } else if (e.key === "ArrowDown") {
    if (lastCmdsIndex < lastCmds.length - 1) {
      ++lastCmdsIndex;
      input.value = lastCmds[lastCmdsIndex];
      cursorToEnd(input);
    } else if (lastCmdsIndex === lastCmds.length - 1) {
      ++lastCmdsIndex;
      input.value = tmpCmd;
      cursorToEnd(input);
    }
  } else {
    if (lastCmdsIndex === lastCmds.length) {
      setTmpCmd(input.value);
    }
  }
};
```

--------------------------------

### Send Command on Button Click

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Attaches a click event listener to the 'send' button to send the current input value as a command and clear the input field.

```javascript
document.getElementById("send").onclick = function () {
  sendCommand(input.value);
  input.value = "";
  setTmpCmd("");
  input.focus();
};
```

--------------------------------

### Discover DOM Properties

Source: https://github.com/nmrugg/stockfish.js/blob/master/node_modules/uglify-js/tools/domprops.html

This code recursively explores DOM objects to discover properties. It handles functions, objects, and their prototypes, adding unique objects to a list. It includes a mechanism to limit the exploration and display the results.

```javascript
if (/^on/.test(k)) addEvent(k.slice(2)); if (!full) try { add(o[k]); } catch (e) {} }); } catch (e) {} if (skip || full) continue; try { add(o.__proto__); } catch (e) {} try { add(o.prototype); } catch (e) {} try { add(new o()); } catch (e) {} try { add(o()); } catch (e) {} } if (!full && objs.length > 20000) { alert(objs.length); full = true; } if (i < objs.length) { setTimeout(next, 0); } else { document.write('<pre>[
 "' + domprops.sort().join('",
 "').replace(/&/g, "&amp;").replace(/</g, "&lt;") + '"\n]</pre>'); } }, 0); function add(o) { if (o) switch (typeof o) { case "function": case "object": if (!~indexOf(objs, o)) objs.push(o); } } function indexOf(list, value) { var j = list.length; while (--j >= 0) { if (list[j] === value) break; } return j; } }(function() { return this; }());
```

--------------------------------

### Parse URL Parameters

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Parses URL query parameters into a JavaScript object. Handles URL encoding and type conversion for values (numbers, booleans).

```javascript
function getParams() {
  var params = {};
  var sep1 = location.search.split(/\&|\?/g);
  var sep2;
  var i;
  var len;
  len = sep1.length;
  if (len > 1) {
    ///NOTE: Skip the first empty element (it's empty because URL's start with a slash).
    for (i = 1; i < len; i += 1) {
      sep2 = sep1[i].split(/=/);
      sep2[0] = decodeURIComponent(sep2[0].replace(/\+/g, " "));
      if (sep2[1]) {
        sep2[1] = decodeURIComponent(sep2[1]).replace(/\+/g, " ");
        /// Convert numbers to Numbers.
        if (+sep2[1] === +sep2[1]) {
          sep2[1] = +sep2[1];
        } else if (sep2[1] === "false") {
          sep2[1] = false;
        } else if (sep2[1] === "true") {
          sep2[1] = true;
        }
      } else {
        sep2[1] = true;
      }
      if (typeof params[sep2[0]] === "undefined") {
        params[sep2[0]] = sep2[1];
      } else {
        if (typeof params[sep2[0]] !== "object") {
          params[sep2[0]] = [params[sep2[0]]];
        }
        params[sep2[0]].push(sep2[1]);
      }
    }
    return params;
  }
}
```

--------------------------------

### Remove Duplicate Commands in Reverse Order

Source: https://github.com/nmrugg/stockfish.js/blob/master/examples/index.html

Removes duplicate commands from an array while preserving the order of the first occurrence. Modifies the array in place.

```javascript
function removeDupsRev(arr) {
  var unique = {};
  var i;
  var len = arr.length;
  var dups = {};
  for (i = len - 1; i >= 0; --i) {
    if (!unique[arr[i]]) {
      unique[arr[i]] = 1;
    } else {
      dups[arr[i]] = 1;
      arr.splice(i, 1); //++i;
    }
  }
  return arr;
}
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.