occurrence

amit265 · amit265 · commit 95e9ebcc8bb8 · 2026-04-14T23:12:45.000+05:30
diff --git a/javascript/5_string-programs/occurrenceLetter.js b/javascript/5_string-programs/occurrenceLetter.js
@@ -0,0 +1,43 @@
+// 17. Get Number of Occurrences of Each Letter
+
+// [Method 1]: Using Object
+
+{
+  function freqCount(s) {
+    const freq = {};
+    for (let x of s) {
+      freq[x] = (freq[x] || 0) + 1;
+    }
+    return freq;
+  }
+
+  console.log(freqCount("amitkumar"));
+}
+
+// [Method 2]: Using Map
+
+{
+  function freqCount(s) {
+    const m = new Map();
+    for (let x of s) {
+      m.set(x, (m.get(x) || 0) + 1);
+    }
+
+    return m;
+  }
+
+  console.log(freqCount("amit"));
+}
+
+// [Method 3]: Using Regular Expression
+
+{
+  function freqCount(s) {
+    return (s.match(/[a-z]/gi) || []).reduce((freq, x) => {
+      freq[x] = (freq[x] || 0) + 1;
+      return freq;
+    }, {});
+  }
+
+  console.log(freqCount("amitamit"));
+}
