Calculadora-Curso-JavaScript/script.js at main · VitorDev01/Calculadora-Curso-JavaScript · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

    const previousOperationText = document.querySelector("#previous-operation");
    const currentOperationText = document.querySelector("#current-operation");
    const buttons = document.querySelectorAll("#buttons-container button");

    class Calculator {
      constructor(previousOperationText, currentOperationText) {
        this.previousOperationText = previousOperationText;
        this.currentOperationText = currentOperationText;
        this.currentOperation = "";
      }

      // add digit to calculator screen
      addDigit(digit) {
        console.log(digit);
        // Check if number already has a dot
        if (digit === "." && this.currentOperationText.innerText.includes(".")) {
          return;
        }

        this.currentOperation = digit;
        this.updateScreen();
      }

      // process all calculator operations
      processOperation(operation) {
        // Check if current value is empty
        if (this.currentOperationText.innerText === "" && operation !== "C") {
          // Change operation
          if (this.previousOperationText.innerText !== "") {
            this.changeOperation(operation);
          }
          return;
        }

        // Get current and previous values
        let operationValue;
        let previous = +this.previousOperationText.innerText.split(" ")[0];
        let current = +this.currentOperationText.innerText;

        switch (operation) {
          case "+":
            operationValue = previous + current;
            this.updateScreen(operationValue, operation, current, previous);
            break;
          case "-":
            operationValue = previous - current;
            this.updateScreen(operationValue, operation, current, previous);
            break;
          case "*":
            operationValue = previous * current;
            this.updateScreen(operationValue, operation, current, previous);
            break;
          case "/":
            operationValue = previous / current;
            this.updateScreen(operationValue, operation, current, previous);
            break;
          case "DEL":
            this.processDelOperator();
            break;
          case "CE":
            this.processClearCurrentOperator();
            break;
          case "C":
            this.processClearOperator();
            break;
          case "=":
            this.processEqualOperator();
            break;
          default:
            return;
        }
      }

      // Change values of calculator screen
      updateScreen(
        operationValue = null,
        operation = null,
        current = null,
        previous = null
      ) {
        if (operationValue === null) {
          // Append number to current value
          this.currentOperationText.innerText += this.currentOperation;
        } else {
          // Check if value is zero, if is just add current value
          if (previous === 0) {
            operationValue = current;
          }
          // Add current value to previous
          this.previousOperationText.innerText = `${operationValue} ${operation}`;
          this.currentOperationText.innerText = "";
        }
      }

      // Change math operation
      changeOperation(operation) {
        const mathOperations = ["*", "-", "+", "/"];

        if (!mathOperations.includes(operation)) {
          return;
        }

        this.previousOperationText.innerText =
          this.previousOperationText.innerText.slice(0, -1) + operation;
      }

      // Delete a digit
      processDelOperator() {
        this.currentOperationText.innerText =
          this.currentOperationText.innerText.slice(0, -1);
      }

      // Clear current operation
      processClearCurrentOperator() {
        this.currentOperationText.innerText = "";
      }

      // Clear all operations
      processClearOperator() {
        this.currentOperationText.innerText = "";
        this.previousOperationText.innerText = "";
      }

      // Process an operation
      processEqualOperator() {
        let operation = this.previousOperationText.innerText.split(" ")[1];

        this.processOperation(operation);
      }
    }

    const calc = new Calculator(previousOperationText, currentOperationText);

    buttons.forEach((btn) => {
      btn.addEventListener("click", (e) => {
        const value = e.target.innerText;

        if (+value >= 0 || value === ".") {
          console.log(value);
          calc.addDigit(value);
        } else {
          calc.processOperation(value);
        }
      });
    });