CalculadoraJS/script.js at master · BrunoLima-dev/CalculadoraJS · GitHub

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/*
TODO:
    Limit number input
    Disallow . from being entered multiple times
    Clean up structure
*/

(function() {
    "use strict";

    // Shortcut to get elements
    var el = function(element) {
      if (element.charAt(0) === "#") { // If passed an ID...
        return document.querySelector(element); // ... returns single element
      }

      return document.querySelectorAll(element); // Otherwise, returns a nodelist
    };

    // Variables
    var viewer = el("#viewer"), // Calculator screen where result is displayed
      igual = el("#igual"), // Equal button
      nums = el(".num"), // List of numbers
      ops = el(".ops"), // List of operators
      theNum = "", // Current number
      oldNum = "", // First number
      resultNum, // Result
      operator; // Batman

    // When: Number is clicked. Get the current number selected
    var setNum = function() {
      if (resultNum) { // If a result was displayed, reset number
        theNum = this.getAttribute("data-num");
        resultNum = "";
      } else { // Otherwise, add digit to previous number (this is a string!)
        theNum += this.getAttribute("data-num");
      }

      viewer.innerHTML = theNum; // Display current number

    };

    // When: Operator is clicked. Pass number to oldNum and save operator
    var moveNum = function() {
      oldNum = theNum;
      theNum = "";
      operator = this.getAttribute("data-ops");

      igual.setAttribute("data-result", ""); // Reset result in attr
    };

    // When: Equals is clicked. Calculate result
    var displayNum = function() {

      // Convert string input to numbers
      oldNum = parseFloat(oldNum);
      theNum = parseFloat(theNum);

      // Perform operation
      switch (operator) {
        case "plus":
          resultNum = oldNum + theNum;
          break;

        case "minus":
          resultNum = oldNum - theNum;
          break;

        case "times":
          resultNum = oldNum * theNum;
          break;

        case "divide":
          resultNum = oldNum / theNum;
          break;

          // If equal is pressed without an operator, keep number and continue
        default:
          resultNum = theNum;
      }

      // If NaN or Infinity returned
      if (!isFinite(resultNum)) {
        if (isNaN(resultNum)) { // If result is not a number; set off by, eg, double-clicking operators
          resultNum = "You broke it!";
        } else { // If result is infinity, set off by dividing by zero
          resultNum = "Look at what you've done";
          el('#calculadora').classList.add("broken"); // Break calculator
          el('#reset').classList.add("show"); // And show reset button
        }
      }

      // Display result, finally!
      viewer.innerHTML = resultNum;
      igual.setAttribute("data-result", resultNum);

      // Now reset oldNum & keep result
      oldNum = 0;
      theNum = resultNum;

    };

    // When: Clear button is pressed. Clear everything
    var clearAll = function() {
      oldNum = "";
      theNum = "";
      viewer.innerHTML = "0";
      igual.setAttribute("data-result", resultNum);
    };

    /* The click events */

    // Add click event to numbers
    for (var i = 0, l = nums.length; i < l; i++) {
      nums[i].onclick = setNum;
    }

    // Add click event to operators
    for (var i = 0, l = ops.length; i < l; i++) {
      ops[i].onclick = moveNum;
    }

    // Add click event to equal sign
    igual.onclick = displayNum;

    // Add click event to clear button
    el("#limpa").onclick = clearAll;

    // Add click event to reset button
    el("#reset").onclick = function() {
      window.location = window.location;
    };

  }());