code for stringArrays

StringsAndTings.js

@@ -1,29 +1,71 @@
 class StringsAndTings {
-
-    // @return string with identical content, and the first character capitalized
-    camelCase(str){
-        return null;
+  // @return string with identical content, and the first character capitalized
+  camelCase(str) {
+    let strSplit = str.split(" ");
+    for (let i = 0; i < strSplit.length; i++) {
+      let word = strSplit[i];
+      strSplit[i] = word[0].toUpperCase() + word.substring(1);
     }
+    return strSplit.join(" ");
+  }
 
-    //@return string with identical contents, with each word individually in reverse order
-    reverseString(str){
-        return null;
-    }
+  //  @return string with identical contents, with each word individually in reverse order
+  reverseString(str) {
+    let result = str.split("").reverse().join("");
+    return result;
+  }
 
-    // @return string with identical contents, in reverse order, with first character capitalized
-    reverseThenCamelCase(str){
-        return null;
+  //  @return string with identical contents, with each word individually in reverse order
+  reverseInPlaceString(str) {
+    let words = str.split(" ");
+    let result = "";
+    for (let i = 0; i < words.length; i++) {
+      let reversedWord = words[i].split("").reverse().join("");
+      words[i] = reversedWord;
     }
+    result = words.join(" ");
+    return result;
+  }
 
-    // @return string with identical contents excluding first and last character
-    removeFirstAndLastCharacter(str){
-        return null;
+  // @return string with identical contents, in reverse order, with first character capitalized
+  reverseThenCamelCase(str) {
+    let reversed = str.toLowerCase().split("").reverse();
+    reversed = reversed.join("").split(" ");
+    let newArr = [];
+    for (let i = 0; i < reversed.length; i++) {
+      let firstLetter = reversed[i].charAt(0).toUpperCase();
+      let restOfWord = reversed[i].slice(1);
+      newArr[i] = firstLetter + restOfWord;
     }
+    return newArr.join(" ");
+  }
 
-    // @return string with identical characters, each with opposite casing
-    invertCasing(str){
-        return null;
-    }
-}
+  // @return string with identical contents excluding first and last character
+  removeFirstAndLastCharacter(str) {
+    let result = str.substr(1, str.length - 2);
+    return result;
+  }
 
-module.exports = StringsAndTings;
+  // @return string with identical characters, each with opposite casing
+  invertCasing(str) {
+    let countChanges = 0;
+    let isLetter = (c) => c.toLowerCase() !== c.toUpperCase();
+    let isLowerCase = (c) => c.toLowerCase() === c;
+
+    let flippedMessage = Array.from(str)
+      .map((c) => {
+        if (!isLetter(c)) {
+          return c;
+        }
+        countChanges++;
+        // return uppercase character if c is a lowercase char
+        if (isLowerCase(c)) {
+          return c.toUpperCase();
+        }
+        // Here, we know c is an uppercase character, so return the lowercase
+        return c.toLowerCase();
+      })
+      .join("");
+      return flippedMessage  }
+}
+module.exports = StringsAndTings;

StringsAndTings.test.js

@@ -8,7 +8,7 @@ test("camelCaseTest", () => {
     let input = "she sells sea shells";
     let expected = "She Sells Sea Shells";
 
-    let actual = stringsAndTings.camelCase(15);
+    let actual = stringsAndTings.camelCase("she sells sea shells");
 
     expect(actual).toEqual(expected);
 });
@@ -19,18 +19,18 @@ test("reverseTest", () => {
     let input = "she sells sea shells";
     let expected = "sllehs aes slles ehs";
 
-    let actual = stringsAndTings.camelCase(15);
+    let actual = stringsAndTings.reverseString(input);
 
     expect(actual).toEqual(expected);
 });
 
-test("reverseWordsTest", () => {
+test("reverseInPlaceStringTest", () => {
 
     let stringsAndTings = new StringsAndTings();
     let input = "she sells sea shells";
     let expected = "ehs slles aes sllehs";
 
-    let actual = stringsAndTings.camelCase(15);
+    let actual = stringsAndTings.reverseInPlaceString(input);
 
     expect(actual).toEqual(expected);
 });
@@ -40,9 +40,7 @@ test("reverseThenCamelCaseTest", () => {
     let stringsAndTings = new StringsAndTings();
     let input = "she sells sea shells";
     let expected = "Sllehs Aes Slles Ehs";
-
-    let actual = stringsAndTings.camelCase(15);
-
+    let actual = stringsAndTings.reverseThenCamelCase(input);
     expect(actual).toEqual(expected);
 });
 
@@ -52,7 +50,7 @@ test("removeFirstAndLastCharacterTest", () => {
     let input = "she sells sea shells";
     let expected = "he sells sea shell";
 
-    let actual = stringsAndTings.camelCase(15);
+    let actual = stringsAndTings.removeFirstAndLastCharacter(input);
 
     expect(actual).toEqual(expected);
 });
@@ -64,8 +62,7 @@ test("invertCasingTest1", () => {
     let input = "shE sells SEA sHeLlS";
     let expected = "SHe SELLS sea ShElLs";
 
-    let actual = stringsAndTings.camelCase(15);
+    let actual = stringsAndTings.invertCasing(input);
 
     expect(actual).toEqual(expected);
 });
-