Merge pull request #63 from wakidurrahman/feat/string-01

JavaScript String Primitive

Author: wakidurrahman

src/exercises/string/exercise-01.ts

@@ -1,2 +1,54 @@
-let a = 'a';
-let b = 'b';
+/**
+ * JavaScript String Primitive
+ * JavaScript's native String primitive comes with various common string functions.
+ *
+ * 1. String Access
+ * 2. String Comparison
+ * 3. String Search
+ * 4. String Decomposition
+ * 5. String Replace
+ */
+
+// 1. String Access
+'Hello world'.charAt(1); // returns 'e';
+'YouTube'.substring(1, 2); // returns 'o' : multiple-character access.
+'YouTube'.substring(3, 7); // returns 'Tube'
+'YouTube'.substring(1); // returns 'ouTube'
+
+// 2. String Comparison
+const a = 'a';
+const b = 'b';
+
+console.log(a < b); // Prints true;
+
+const c = 'add';
+const d = 'ab';
+
+console.log(a < b); // Prints 'false'
+
+// String Search
+
+'Red Dragon'.indexOf('Red'); // returns 0;
+'Red Dragon'.indexOf('RedScale'); // returns -1
+'Red Dragon'.indexOf('Dragon', 0); // returns 4
+
+function existsInString(stringValue: string, search: string) {
+  return stringValue.indexOf(search) !== -1;
+}
+
+console.log(existsInString('red', 'r')); // prints 'true';
+console.log(existsInString('red', 'b')); // prints 'false';
+
+const stringLong = 'He is my king from this day until his last day';
+let count = 0;
+let pos = stringLong.indexOf('a');
+
+while (pos !== -1) {
+  count++;
+  pos = stringLong.indexOf('a', pos + 1);
+}
+
+console.log(count);
+
+'Red Dragon'.startsWith('Red'); // Returns true
+'Red Dragon'.endsWith('Dragon'); // Returns true