261 lines
8.3 KiB
HTML
261 lines
8.3 KiB
HTML
<!--
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Calculator widget.
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This file should contain all required
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CSS, HTML, and JS for it.
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-->
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<style>
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#calc-text {
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background: var(--whoogle-dark-page-bg);
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padding: 8px;
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border-radius: 8px;
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text-align: right;
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font-family: monospace;
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font-size: 16px;
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color: var(--whoogle-dark-text);
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}
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#prev-equation {
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text-align: right;
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}
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.error-border {
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border: 1px solid red;
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}
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#calc-btns {
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display: grid;
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grid-template-columns: repeat(6, 1fr);
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grid-template-rows: repeat(5, 1fr);
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gap: 5px;
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}
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#calc-btns button {
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background: #313141;
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color: var(--whoogle-dark-text);
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border: none;
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border-radius: 8px;
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padding: 8px;
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cursor: pointer;
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}
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#calc-btns button:hover {
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background: #414151;
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}
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#calc-btns .common {
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background: #51516a;
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}
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#calc-btns .common:hover {
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background: #61617a;
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}
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#calc-btn-0 { grid-row: 5; grid-column: 3; }
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#calc-btn-1 { grid-row: 4; grid-column: 3; }
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#calc-btn-2 { grid-row: 4; grid-column: 4; }
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#calc-btn-3 { grid-row: 4; grid-column: 5; }
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#calc-btn-4 { grid-row: 3; grid-column: 3; }
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#calc-btn-5 { grid-row: 3; grid-column: 4; }
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#calc-btn-6 { grid-row: 3; grid-column: 5; }
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#calc-btn-7 { grid-row: 2; grid-column: 3; }
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#calc-btn-8 { grid-row: 2; grid-column: 4; }
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#calc-btn-9 { grid-row: 2; grid-column: 5; }
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#calc-btn-EQ { grid-row: 5; grid-column: 5; }
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#calc-btn-PT { grid-row: 5; grid-column: 4; }
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#calc-btn-BCK { grid-row: 5; grid-column: 6; }
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#calc-btn-ADD { grid-row: 4; grid-column: 6; }
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#calc-btn-SUB { grid-row: 3; grid-column: 6; }
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#calc-btn-MLT { grid-row: 2; grid-column: 6; }
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#calc-btn-DIV { grid-row: 1; grid-column: 6; }
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#calc-btn-CLR { grid-row: 1; grid-column: 5; }
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#calc-btn-PRC{ grid-row: 1; grid-column: 4; }
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#calc-btn-RP { grid-row: 1; grid-column: 3; }
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#calc-btn-LP { grid-row: 1; grid-column: 2; }
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#calc-btn-ABS { grid-row: 1; grid-column: 1; }
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#calc-btn-SIN { grid-row: 2; grid-column: 2; }
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#calc-btn-COS { grid-row: 3; grid-column: 2; }
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#calc-btn-TAN { grid-row: 4; grid-column: 2; }
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#calc-btn-SQR { grid-row: 5; grid-column: 2; }
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#calc-btn-EXP { grid-row: 2; grid-column: 1; }
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#calc-btn-E { grid-row: 3; grid-column: 1; }
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#calc-btn-PI { grid-row: 4; grid-column: 1; }
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#calc-btn-LOG { grid-row: 5; grid-column: 1; }
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</style>
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<p id="prev-equation"></p>
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<div id="calculator-widget">
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<p id="calc-text">0</p>
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<div id="calc-btns">
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<button id="calc-btn-0" class="common">0</button>
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<button id="calc-btn-1" class="common">1</button>
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<button id="calc-btn-2" class="common">2</button>
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<button id="calc-btn-3" class="common">3</button>
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<button id="calc-btn-4" class="common">4</button>
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<button id="calc-btn-5" class="common">5</button>
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<button id="calc-btn-6" class="common">6</button>
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<button id="calc-btn-7" class="common">7</button>
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<button id="calc-btn-8" class="common">8</button>
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<button id="calc-btn-9" class="common">9</button>
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<button id="calc-btn-EQ" class="common">=</button>
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<button id="calc-btn-PT" class="common">.</button>
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<button id="calc-btn-BCK">⬅</button>
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<button id="calc-btn-ADD">+</button>
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<button id="calc-btn-SUB">-</button>
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<button id="calc-btn-MLT">x</button>
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<button id="calc-btn-DIV">/</button>
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<button id="calc-btn-CLR">C</button>
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<button id="calc-btn-PRC">%</button>
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<button id="calc-btn-RP">)</button>
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<button id="calc-btn-LP">(</button>
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<button id="calc-btn-ABS">|x|</button>
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<button id="calc-btn-SIN">sin</button>
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<button id="calc-btn-COS">cos</button>
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<button id="calc-btn-TAN">tan</button>
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<button id="calc-btn-SQR">√</button>
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<button id="calc-btn-EXP">^</button>
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<button id="calc-btn-E">ℇ</button>
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<button id="calc-btn-PI">π</button>
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<button id="calc-btn-LOG">log</button>
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</div>
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</div>
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<script>
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// JS does not have this by default.
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// from https://www.freecodecamp.org/news/how-to-factorialize-a-number-in-javascript-9263c89a4b38/
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function factorial(num) {
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if (num < 0)
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return -1;
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else if (num === 0)
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return 1;
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else {
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return (num * factorial(num - 1));
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}
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}
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// returns true if the user is currently focused on the calculator widget
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function usingCalculator() {
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let activeElement = document.activeElement;
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while (true) {
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if (!activeElement) return false;
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if (activeElement.id === "calculator-wrapper") return true;
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activeElement = activeElement.parentElement;
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}
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}
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const $ = q => document.querySelectorAll(q);
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// key bindings for commonly used buttons
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const keybindings = {
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"0": "0",
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"1": "1",
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"2": "2",
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"3": "3",
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"4": "4",
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"5": "5",
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"6": "6",
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"7": "7",
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"8": "8",
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"9": "9",
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"Enter": "EQ",
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".": "PT",
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"+": "ADD",
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"-": "SUB",
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"*": "MLT",
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"/": "DIV",
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"%": "PRC",
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"c": "CLR",
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"(": "LP",
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")": "RP",
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"Backspace": "BCK",
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}
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window.addEventListener("keydown", event => {
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if (!usingCalculator()) return;
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if (event.key === "Enter" && document.activeElement.id !== "search-bar")
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event.preventDefault();
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if (keybindings[event.key])
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document.getElementById("calc-btn-" + keybindings[event.key]).click();
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})
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// calculates the string
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const calc = () => {
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var mathtext = document.getElementById("calc-text");
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var statement = mathtext.innerHTML
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// remove empty ()
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.replace("()", "")
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// special constants
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.replace("π", "(Math.PI)")
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.replace("ℇ", "(Math.E)")
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// turns 3(1+2) into 3*(1+2) (for example)
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.replace(/(?<=[0-9\)])(?<=[^+\-x*\/%^])\(/, "x(")
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// same except reversed
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.replace(/\)(?=[0-9\(])(?=[^+\-x*\/%^])/, ")x")
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// replace human friendly x with JS *
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.replace("x", "*")
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// trig & misc functions
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.replace("sin", "Math.sin")
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.replace("cos", "Math.cos")
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.replace("tan", "Math.tan")
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.replace("√", "Math.sqrt")
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.replace("^", "**")
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.replace("abs", "Math.abs")
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.replace("log", "Math.log")
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;
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// add any missing )s to the end
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while(true) if (
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(statement.match(/\(/g) || []).length >
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(statement.match(/\)/g) || []).length
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) statement += ")"; else break;
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// evaluate the expression.
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console.log("calculating [" + statement + "]");
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try {
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var result = eval(statement);
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document.getElementById("prev-equation").innerHTML = mathtext.innerHTML + " = ";
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mathtext.innerHTML = result;
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mathtext.classList.remove("error-border");
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} catch (e) {
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mathtext.classList.add("error-border");
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console.error(e);
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}
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}
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const updateCalc = (e) => {
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// character(s) recieved from button
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var c = event.target.innerHTML;
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var mathtext = document.getElementById("calc-text");
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if (mathtext.innerHTML === "0") mathtext.innerHTML = "";
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// special cases
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switch (c) {
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case "C":
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// Clear
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mathtext.innerHTML = "0";
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break;
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case "⬅":
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// Delete
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mathtext.innerHTML = mathtext.innerHTML.slice(0, -1);
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if (mathtext.innerHTML.length === 0) {
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mathtext.innerHTML = "0";
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}
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break;
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case "=":
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calc()
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break;
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case "sin":
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case "cos":
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case "tan":
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case "log":
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case "√":
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mathtext.innerHTML += `${c}(`;
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break;
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case "|x|":
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mathtext.innerHTML += "abs("
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break;
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case "+":
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case "-":
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case "x":
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case "/":
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case "%":
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case "^":
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if (mathtext.innerHTML.length === 0) mathtext.innerHTML = "0";
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// prevent typing 2 operators in a row
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if (mathtext.innerHTML.match(/[+\-x\/%^] $/))
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mathtext.innerHTML = mathtext.innerHTML.slice(0, -3);
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mathtext.innerHTML += ` ${c} `;
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break;
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default:
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mathtext.innerHTML += c;
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}
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}
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for (let i of $("#calc-btns button")) {
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i.addEventListener('click', event => {
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updateCalc(event);
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})
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}
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</script>
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