1 files changed, 109 insertions, 0 deletions
diff --git a/apps/Calculator/components/App.js b/apps/Calculator/components/App.js
new file mode 100644
index 0000000..df46751
--- /dev/null
+++ b/apps/Calculator/components/App.js
@@ -0,0 +1,109 @@
+import { useState } from 'react';
+import styles from '../styles/Calculator.module.scss'
+
+const App = () => {
+  const [display, setDisplay] = useState('0')
+  const [memory, setMemory] = useState([])
+  const [result, setResult] = useState([])
+
+  const onClear = () => {
+    setDisplay('0')
+    setMemory([])
+  }
+  const onNumber = n => setDisplay(p => display === '0' ? n.toString() : p+n)
+  const onMath = m => {
+    if (display !== '0') {
+      if (!result) {
+        setMemory(p => [
+          ...p,
+          { type: 'n', value: display },
+          { type: 'm', value: m },
+        ]);
+      } else {
+        setResult(false)
+        setMemory([
+          { type: 'n', value: display },
+          { type: 'm', value: m },
+        ]);
+      }
+      setDisplay('0')
+    } else if (memory[memory.length - 1].type === 'm') {
+      setMemory(p => [...p.slice(0, -1), { type: 'm', value: m }]);
+    }
+  }
+
+  const newVal = (prevVal, curVal) => {
+    if (!prevVal || !prevVal.m) return 0;
+
+    if (prevVal.m === '+') {
+      return `${Number(prevVal.value) + Number(curVal.value)}`
+    }
+    if (prevVal.m === '-') {
+      return `${Number(prevVal.value) - Number(curVal.value)}`
+    }
+    if (prevVal.m === '*') {
+      return `${Number(prevVal.value) * Number(curVal.value)}`
+    }
+    if (prevVal.m === '/') {
+      return prevVal.value !== '0' && curVal.value !== '0'
+        ? `${Number(prevVal.value) / Number(curVal.value)}`
+        : '0'
+    }
+  }
+
+  const onResult = () => {
+    if (memory.length > 2 || (memory.length > 1 && display !== '0')) {
+      const actions = display === 0
+        ? memory
+        : [...memory, { type: 'n', value: display }]
+      const result = actions.reduce((prevVal, curVal) => {
+        return curVal.type === 'n'
+          ? ({ value: newVal(prevVal, curVal), m: null })
+          : ({ value: prevVal.value, m: curVal.value })
+      })
+      setDisplay(result?.value || 0);
+      setResult(true)
+      if (display !== 0) {
+        setMemory(p => [...p, { type: 'n', value: display }])
+      }
+    }
+  }
+
+  return (
+    <>
+      <div className='window__submenu'>
+        <div>
+          <div onClick={onClear}>
+            Clear
+          </div>
+        </div>
+      </div>
+      <div className={styles.calculator}>
+        <div className={styles.display}>
+          <div>
+            { memory.map(o => o.value).join(' ') }
+          </div>
+          <div>
+            {display}
+          </div>
+        </div>
+        <div className={styles.keys}>
+          <div>
+            { [...Array(10).keys()].map(k => (
+              <div key={k} onClick={() => onNumber(k)}>{k}</div>
+            )) }
+            <div onClick={() => setDisplay(p => p+'.')}>.</div>
+            <div onClick={onResult}>=</div>
+          </div>
+          <div>
+            {['+','-','*','/'].map(m => (
+              <div key={m} onClick={() => onMath(m)}>{m}</div>
+            ))}
+          </div>
+        </div>
+      </div>
+    </>
+  )
+}
+
+export default App