81 lines
No EOL
2.2 KiB
JavaScript
81 lines
No EOL
2.2 KiB
JavaScript
const screen = document.querySelector(".screen");
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const buttons = document.querySelectorAll("button");
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const operators = ["+", "-", "*", "/"];
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buttons.forEach((button) => {
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button.addEventListener ("click", displayToScreen);
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});
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function displayToScreen() {
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if (this.className == "equal") {
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let calc = new Calculator;
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screen.textContent = calc.calculate(screen.textContent);
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} else if (this.className == "clear") {
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screen.textContent = "0";
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} else if (this.className == "back") {
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screen.textContent = screen.textContent.trimEnd()
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screen.textContent = screen.textContent.slice(0, -1);
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if (!isNaN(screen.textContent.charAt(-2))) {
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screen.textContent = screen.textContent.trimEnd()
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}
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} else {
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if (this.className == "operator") {
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let screenContent = screen.textContent;
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// Add some logic for handling negatives with -
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// Handle decimals add 0 on a trailing decimal point
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// Add key support
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for (let i = 0; i < screenContent.length; i++ ) {
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if (operators.includes(screenContent[i])) {
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let calc = new Calculator;
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result = calc.calculate(screen.textContent);
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screen.textContent = result;
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break;
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}
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}
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screen.textContent += " " + this.textContent + " ";
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} else if (screen.textContent === "0" && this.className == "num") {
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screen.textContent = this.textContent;
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} else {
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screen.textContent += this.textContent;
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}
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}
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}
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function Calculator(str) {
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console.log("Calculator has been called")
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this.methods = {
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"-": (a, b) => (a - b),
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"+": (a, b) => (a + b),
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"/": (a, b) => (a / b),
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"*": (a, b) => (a * b)
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};
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this.calculate = function(str) {
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let parts = str.split(" ");
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a = +parts[0];
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op = parts[1];
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b = +parts[2];
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if (a && !b) {
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return a;
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}
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if (isNaN(a) || isNaN(b)) {
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return NaN;
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}
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if (!this.methods[op]) {
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return "Operation not supported."
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}
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return this.methods[op](a, b);
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};
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} |