Add natural logarithm (ln) unary operator to calculator #1

Copilot · 2025-11-05T22:20:31Z

Implements ln as a unary operation that computes the natural logarithm immediately when pressed, without requiring a second operand.

Changes

UI (public/index.html)

Added ln button before the ^ button

Client (public/client.js)

Added ln case to calculate() switch statement mapping to ?operation=ln
Modified operationPressed() to detect ln and immediately call calculate(operand1, 0, 'ln')

Server (api/controller.js)

Added ln operation: ln: function (a) { return Math.log(Number(a)); }
Updated validation to skip operand2 check when operation === 'ln'

Usage

// User enters 10, presses ln → displays ~2.302585
operationPressed('ln') 
  → calculate(10, 0, 'ln') 
  → GET /arithmetic?operation=ln&operand1=10&operand2=0
  → { result: 2.302585092994046 }

Tests for the ln operation can be added in a follow-up PR.

Original prompt

Create a new branch named add-ln-button and open a pull request against main that implements an "ln" (natural logarithm) unary operation. Changes to make:

public/index.html

Add a new calculator button labeled "ln" that calls operationPressed('ln'). Place it near the other operator buttons (next to the ^ button).

Replace the calculator-buttons block content with the same structure but with the ln button inserted before the ^ button. The rest of the file should remain unchanged.

Provide the final content of public/index.html (only the file content to write) matching the existing project layout but including the new button. Use the existing <script src="client.js"></script> and body onLoad handler.

public/client.js

Update calculate() to handle the 'ln' operation by mapping it to ?operation=ln in the URI.
Update operationPressed(op) so that when op === 'ln' it treats ln as a unary operator: it should read operand1 = getValue(), set state to complete, and immediately call calculate(operand1, 0, 'ln') (we can pass a dummy operand2=0 since server will ignore operand2 for ln).
Ensure other behavior remains unchanged.

Provide the full updated public/client.js file content to be written.

api/controller.js

Add an 'ln' operation to the operations map that computes Math.log(Number(a)) (natural log) and ignores operand2.
Adjust input validation so that operand2 is not required for the 'ln' operation; for other operations operand2 validation remains.

Provide the full updated api/controller.js file content to be written.

Additional notes for the PR description (include in the PR body):

Explain that ln is a unary operator (natural logarithm), how the UI behaves (user types a number then presses ln and gets result immediately), and that server computes Math.log on operand1.
Mention tests are not added in this change and could be added in a follow-up PR.

Commit message: "Add ln (natural log) button and server/client support"
Branch name: add-ln-button

Please create the branch, commit the three updated files, and open a pull request with the title and description above.

Files to change (final contents to write):

<html>
  <head>
    <title>Calculator</title>
    <link rel="stylesheet" href="default.css" />
    <meta
      name="viewport"
      content="width=device-width, initial-scale=1.0, maximum-scale=1.0"
    />
    <script src="client.js"></script>
  </head>
  <body onLoad="setValue(0)">
    <div class="container">
      <div id="results">
        <div id="result"><span class="digit0">0</span></div>
      </div>

      <div id="loading" style="visibility: hidden"></div>

      <div class="box">
        <div class="calculator">
          <div class="calculator-buttons">
            <button class="btn span-2"></button>
            <button class="btn" onClick="clearPressed()">C</button>
            <button class="btn" onClick="clearPressed()">CE</button>

            <button class="btn" onClick="numberPressed(7)">7</button>
            <button class="btn" onClick="numberPressed(8)">8</button>
            <button class="btn" onClick="numberPressed(9)">9</button>
            <button class="btn" onClick="operationPressed('/')">
              &divide;
            </button>

            <button class="btn" onClick="numberPressed(4)">4</button>
            <button class="btn" onClick="numberPressed(5)">5</button>
            <button class="btn" onClick="numberPressed(6)">6</button>
            <button class="btn" onClick="operationPressed('*')">x</button>

            <button class="btn" onClick="numberPressed(1)">1</button>
            <button class="btn" onClick="numberPressed(2)">2</button>
            <button class="btn" onClick="numberPressed(3)">3</button>
            <button class="btn" onClick="operationPressed('-')">-</button>

            <button class="btn" onClick="numberPressed(0)">0</button>
            <button class="btn" onClick="decimalPressed()">.</button>
            <button class="btn" onClick="operationPressed('+')">+</button>

            <!-- New natural log (ln) unary operator button -->
            <button class="btn" onClick="operationPressed('ln')">ln</button>

            <button class="btn" onClick="operationPressed('^')">^</button>

            <button class="btn span-4" onClick="equalPressed()">=</button>
          </div>
        </div>
      </div>
    </div>
  </body>
</html>

"use strict";

var value = 0;

var states = {
  start: 0,
  operand1: 1,
  operator: 2,
  operand2: 3,
  complete: 4,
};

var state = states.start;

var operand1 = 0;
var operand2 = 0;
var operation = null;

function calculate(operand1, operand2, operation) {
  var uri = location.origin + "/arithmetic";

  switch (operation) {
    case "+":
      uri += "?operation=add";
      break;
    case "-":
      uri += "?operation=subtract";
      break;
    case "*":
      uri += "?operation=multiply";
      break;
    case "/":
      uri += "?operation=divide";
 ...

</details>

*This pull request was created as a result of the following prompt from Copilot chat.*
> Create a new branch named `add-ln-button` and open a pull request against `main` that implements an "ln" (natural logarithm) unary operation. Changes to make:
> 
> 1) public/index.html
> - Add a new calculator button labeled "ln" that calls operationPressed('ln'). Place it near the other operator buttons (next to the ^ button).
> 
> Replace the calculator-buttons block content with the same structure but with the ln button inserted before the ^ button. The rest of the file should remain unchanged.
> 
> Provide the final content of public/index.html (only the file content to write) matching the existing project layout but including the new button. Use the existing <script src="client.js"></script> and body onLoad handler.
> 
> 2) public/client.js
> - Update calculate() to handle the 'ln' operation by mapping it to `?operation=ln` in the URI.
> - Update operationPressed(op) so that when op === 'ln' it treats ln as a unary operator: it should read operand1 = getValue(), set state to complete, and immediately call calculate(operand1, 0, 'ln') (we can pass a dummy operand2=0 since server will ignore operand2 for ln).
> - Ensure other behavior remains unchanged.
> 
> Provide the full updated public/client.js file content to be written.
> 
> 3) api/controller.js
> - Add an 'ln' operation to the operations map that computes Math.log(Number(a)) (natural log) and ignores operand2.
> - Adjust input validation so that operand2 is not required for the 'ln' operation; for other operations operand2 validation remains.
> 
> Provide the full updated api/controller.js file content to be written.
> 
> Additional notes for the PR description (include in the PR body):
> - Explain that ln is a unary operator (natural logarithm), how the UI behaves (user types a number then presses ln and gets result immediately), and that server computes Math.log on operand1.
> - Mention tests are not added in this change and could be added in a follow-up PR.
> 
> Commit message: "Add ln (natural log) button and server/client support"
> Branch name: add-ln-button
> 
> Please create the branch, commit the three updated files, and open a pull request with the title and description above.
> 
> Files to change (final contents to write):
> 
> ```html
> <html>
>   <head>
>     <title>Calculator</title>
>     <link rel="stylesheet" href="default.css" />
>     <meta
>       name="viewport"
>       content="width=device-width, initial-scale=1.0, maximum-scale=1.0"
>     />
>     <script src="client.js"></script>
>   </head>
>   <body onLoad="setValue(0)">
>     <div class="container">
>       <div id="results">
>         <div id="result"><span class="digit0">0</span></div>
>       </div>
> 
>       <div id="loading" style="visibility: hidden"></div>
> 
>       <div class="box">
>         <div class="calculator">
>           <div class="calculator-buttons">
>             <button class="btn span-2"></button>
>             <button class="btn" onClick="clearPressed()">C</button>
>             <button class="btn" onClick="clearPressed()">CE</button>
> 
>             <button class="btn" onClick="numberPressed(7)">7</button>
>             <button class="btn" onClick="numberPressed(8)">8</button>
>             <button class="btn" onClick="numberPressed(9)">9</button>
>             <button class="btn" onClick="operationPressed('/')">
>               &divide;
>             </button>
> 
>             <button class="btn" onClick="numberPressed(4)">4</button>
>             <button class="btn" onClick="numberPressed(5)">5</button>
>             <button class="btn" onClick="numberPressed(6)">6</button>
>             <button class="btn" onClick="operationPressed('*')">x</button>
> 
>             <button class="btn" onClick="numberPressed(1)">1</button>
>             <button class="btn" onClick="numberPressed(2)">2</button>
>             <button class="btn" onClick="numberPressed(3)">3</button>
>             <button class="btn" onClick="operationPressed('-')">-</button>
> 
>             <button class="btn" onClick="numberPressed(0)">0</button>
>             <button class="btn" onClick="decimalPressed()">.</button>
>             <button class="btn" onClick="operationPressed('+')">+</button>
> 
>             <!-- New natural log (ln) unary operator button -->
>             <button class="btn" onClick="operationPressed('ln')">ln</button>
> 
>             <button class="btn" onClick="operationPressed('^')">^</button>
> 
>             <button class="btn span-4" onClick="equalPressed()">=</button>
>           </div>
>         </div>
>       </div>
>     </div>
>   </body>
> </html>
> ```
> 
> ```javascript
> "use strict";
> 
> var value = 0;
> 
> var states = {
>   start: 0,
>   operand1: 1,
>   operator: 2,
>   operand2: 3,
>   complete: 4,
> };
> 
> var state = states.start;
> 
> var operand1 = 0;
> var operand2 = 0;
> var operation = null;
> 
> function calculate(operand1, operand2, operation) {
>   var uri = location.origin + "/arithmetic";
> 
>   switch (operation) {
>     case "+":
>       uri += "?operation=add";
>       break;
>     case "-":
>       uri += "?operation=subtract";
>       break;
>     case "*":
>       uri += "?operation=multiply";
>       break;
>     case "/":
>       uri += "?operation=divide";
>       break;
>     case "^":
>       uri += "?operation=power";
>       break;
>     case "ln":
>       uri += "?operation=ln";
>       break;
>     default:
>       setError();
>       return;
>   }
> 
>   uri += "&operand1=" + encodeURIComponent(operand1);
>   uri += "&operand2=" + encodeURIComponent(operand2);
> 
>   setLoading(true);
> 
>   var http = new XMLHttpRequest();
>   http.open("GET", uri, true);
>   http.onload = function () {
>     setLoading(false);
> 
>     if (http.status == 200) {
>       var response = JSON.parse(http.responseText);
>       setValue(response.result);
>     } else {
>       setError();
>     }
>   };
>   http.send(null);
> }
> 
> function clearPressed() {
>   setValue(0);
> 
>   operand1 = 0;
>   operand2 = 0;
>   operation = null;
>   state = states.start;
> }
> 
> function clearEntryPressed() {
>   setValue(0);
>   state = state == states.operand2 ? states.operator : states.start;
> }
> 
> function numberPressed(n) {
>   var value = getValue();
> 
>   if (state == states.start || state == states.complete) {
>     value = n;
>     state = n == "0" ? states.start : states.operand1;
>   } else if (state == states.operator) {
>     value = n;
>     state = n == "0" ? states.operator : states.operand2;
>   } else if (value.replace(/[-\.]/g, "").length < 8) {
>     value += n;
>   }
> 
>   value += "";
> 
>   setValue(value);
> }
> 
> function decimalPressed() {
>   if (state == states.start || state == states.complete) {
>     setValue("0.");
>     state = states.operand1;
>   } else if (state == states.operator) {
>     setValue("0.");
>     state = states.operand2;
>   } else if (!getValue().toString().includes(".")) {
>     setValue(getValue() + ".");
>   }
> }
> 
> function signPressed() {
>   var value = getValue();
> 
>   if (value != 0) {
>     setValue(-1 * value);
>   }
> }
> 
> function operationPressed(op) {
>   // store operand1
>   operand1 = getValue();
>   operation = op;
> 
>   // ln is a unary operator (natural log) — compute immediately using operand1
>   if (op === "ln") {
>     state = states.complete;
>     calculate(operand1, 0, operation);
>     return;
>   }
> 
>   state = states.operator;
> }
> 
> function equalPressed() {
>   if (state < states.operand2) {
>     state = states.complete;
>     return;
>   }
> 
>   if (state == states.operand2) {
>     operand2 = getValue();
>     state = states.complete;
>   } else if (state == states.complete) {
>     operand1 = getValue();
>   }
> 
>   calculate(operand1, operand2, operation);
> }
> 
> // TODO: Add key press logics
> document.addEventListener("keypress", (event) => {
>   if (event.key.match(/^\d+$/)) {
>     numberPressed(event.key);
>   } else if (event.key == ".") {
>     decimalPressed();
>   } else if (event.key.match(/^[-*+\/]$/)) {
>     operationPressed(event.key);
>   } else if (event.key == "=") {
>     equalPressed();
>   }
> });
> 
> function getValue() {
>   return value;
> }
> 
> function setValue(n) {
>   value = n;
> 
>   var displayValue = value;
> 
>   if (displayValue > 99999999) {
>     displayValue = displayValue.toExponential(4);
>   } else if (displayValue < -99999999) {
>     displayValue = displayValue.toExponential(4);
>   } else if (displayValue > 0 && displayValue < 0.0000001) {
>     displayValue = displayValue.toExponential(4);
>   } else if (displayValue < 0 && displayValue > -0.0000001) {
>     displayValue = displayValue.toExponential(3);
>   }
> 
>   var chars = displayValue.toString().split("");
>   var html = "";
> 
>   for (var c of chars) {
>     if (c == "-") {
>       html += '<span class="resultchar negative">' + c + "</span>";
>     } else if (c == ".") {
>       html += '<span class="resultchar decimal">' + c + "</span>";
>     } else if (c == "e") {
>       html += '<span class="resultchar exponent">' + c + "</span>";
>     } else {
>       html += '<span class="resultchar digit' + c + '">' + c + "</span>";
>     }
>   }
> 
>   document.getElementById("result").innerHTML = html;
> }
> 
> function setError(n) {
>   document.getElementById("result").innerHTML = "ERROR";
> }
> 
> function setLoading(loading) {
>   if (loading) {
>     document.getElementById("loading").style.visibility = "visible";
>   } else {
>     document.getElementById("loading").style.visibility = "hidden";
>   }
> 
>   var buttons = document.querySelectorAll("BUTTON");
> 
>   for (var i = 0; i < buttons.length; i++) {
>     buttons[i].disabled = loading;
>   }
> }
> ```
> 
> ```javascript
> "use strict";
> 
> exports.calculate = function (req, res) {
>   req.app.use(function (err, _req, res, next) {
>     if (res.headersSent) {
>       return next(err);
>     }
> 
>     res.status(400);
>     res.json({ error: err.message });
>   });
> 
>   var operations = {
>     add: function (a, b) {
>       return Number(a) + Number(b);
>     },
>     subtract: function (a, b) {
>       return a - b;
>     },
>     multiply: function (a, b) {
>       return a * b;
>     },
>     divide: function (a, b) {
>       return a / b;
>     },
>     power: function (a, b) {
>       return Math.pow(a, b);
>     },
>     // natural logarithm (ln) - uses only operand1
>     ln: function (a, b) {
>       return Math.log(Number(a));
>     },
>   };
> 
>   if (!req.query.operation) {
>     throw new Error("Unspecified operation");
>   }
> 
>   var operation = operations[req.query.operation];
> 
>   if (!operation) {
>     throw new Error("Invalid operation: " + req.query.operation);
>   }
> 
>   if (
>     !req.query.operand1 ||
>     req.query.operand1.toString().length === 0
>   ) {
>     throw new Error("Operand1 missing");
>   }
> 
>   // For unary ops like ln we don't require operand2; for others we do
>   if (req.query.operation !== "ln") {
>     if (
>       !req.query.operand2 ||
>       req.query.operand2.toString().length === 0
>     ) {
>       throw new Error("Operand2 missing");
>     }
>   }
> 
>   var result = operation(req.query.operand1, req.query.operand2);
> 
>   res.json({ result: result });
> };
> ```
> 

<!-- START COPILOT CODING AGENT TIPS -->
---

✨ Let Copilot coding agent [set things up for you](https://github.com/sdley/ps-github-foundations-github-copilot/issues/new?title=✨+Set+up+Copilot+instructions&body=Configure%20instructions%20for%20this%20repository%20as%20documented%20in%20%5BBest%20practices%20for%20Copilot%20coding%20agent%20in%20your%20repository%5D%28https://gh.io/copilot-coding-agent-tips%29%2E%0A%0A%3COnboard%20this%20repo%3E&assignees=copilot) — coding agent works faster and does higher quality work when set up for your repo.

Co-authored-by: sdley <[email protected]>

Initial plan

fd8c544

Copilot AI assigned Copilot and sdley Nov 5, 2025

Copilot started work on behalf of sdley November 5, 2025 22:31 View session

Copilot AI and others added 2 commits November 5, 2025 22:37

Add ln (natural log) button and server/client support

ae34179

Co-authored-by: sdley <[email protected]>

Improve ln function signature to only accept one parameter

b83f3a6

Co-authored-by: sdley <[email protected]>

Copilot AI changed the title ~~[WIP] Add ln button for natural logarithm operation~~ Add natural logarithm (ln) unary operator to calculator Nov 5, 2025

Copilot AI requested a review from sdley November 5, 2025 22:44

Copilot finished work on behalf of sdley November 5, 2025 22:44

sdley marked this pull request as ready for review November 5, 2025 22:53

sdley approved these changes Nov 5, 2025

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