How to make a calculator in JavaScript?

Making a calculator in JavaScript is a good beginner project for developers who are just starting with the language. Here’s a step-by-step guide to creating a simple calculator:

1. Set up the HTML structure: Create an HTML file and include the necessary elements, such as the calculator display and the buttons.

<div id="calculator">
  <input type="text" id="display">
  <button id="button-1">1</button>
  <button id="button-2">2</button>
  <button id="button-3">3</button>
  <button id="button-plus">+</button>
  <button id="button-4">4</button>
  <button id="button-5">5</button>
  <button id="button-6">6</button>
  <button id="button-minus">-</button>
  <button id="button-7">7</button>
  <button id="button-8">8</button>
  <button id="button-9">9</button>
  <button id="button-multiply">*</button>
  <button id="button-clear">C</button>
  <button id="button-0">0</button>
  <button id="button-equals">=</button>
  <button id="button-divide">/</button>
</div>

2. Style the calculator using CSS: Use CSS to style the calculator display and the buttons, giving them a specific look and feel.
3. Create the JavaScript logic: Using JavaScript, create a function for each button that updates the display and performs the corresponding operation when a button is clicked. You’ll also need to create a function that clears the display and resets the calculator.

let display = document.getElementById("display");

function updateDisplay(value) {
  display.value += value;
}

function clearDisplay() {
  display.value = "";
}

function calculate() {
  let result = eval(display.value);
  display.value = result;
}

4. Add event listeners: Use JavaScript to add event listeners to the buttons so that the corresponding function is called when the button is clicked.

document.getElementById("button-1").addEventListener("click", function() {
  updateDisplay("1");
});

document.getElementById("button-2").addEventListener("click", function() {
  updateDisplay("2");
});

document.getElementById("button-3").addEventListener("click", function() {
  updateDisplay("3");
});

// Repeat for all the other buttons

document.getElementById("button-clear").addEventListener("click", function() {
  clearDisplay();
});

document.getElementById("button-equals").addEventListener("click", function() {
  calculate();
});

5. Test and debug the calculator: Test the calculator thoroughly and fix any bugs or issues that arise.

Here are some resources to help you get started with making a calculator in JavaScript:

• Calculator tutorial by JavaScript for Cats: https://www.javascriptforcats.com/projects/calculator/
• Calculator tutorial by W3Schools: https://www.w3schools.com/howto/howto_js_calculator.asp
• Calculator tutorial by CodePen: https://codepen.io/andrewblodgett/pen/ExYQrLx

Good luck with your project!

<template>
  <ul>
    <li v-for="item in items" :key="item.id">
      {{ item.name }}
    </li>
  </ul>
</template>

<script>
export default {
  props: {
    items: {
      type: Array,
      required: true,
    },
  },
};
</script>