working code added for all problems except reverseThenCamelCase

StringsAndTings.js

@@ -1,28 +1,85 @@
 class StringsAndTings {
 
     // @return string with identical content, and the first character capitalized
+    // camelCase(str){
+    //     let input = "she sells sea shells";
+    //     let string = input.split(" ");
+    //     for (let i = 0; i <string.length; i++) {
+    //         string[i] = string[i][0].toUpperCase() + string[i].substr(1);
+
+    //     }
+
+    //     return string.join(" ");
+    // }
+
+
     camelCase(str){
-        return null;
+        let string = str.split(" ");
+        for (let i = 0; i <string.length; i++) {
+            string[i] = string[i][0].toUpperCase() + string[i].substring(1);
+        }
+        return string.join(" ");
     }
 
+
+
     //@return string with identical contents, with each word individually in reverse order
     reverseString(str){
-        return null;
+        let rString = "";
+        for (let i = str.length-1; i >= 0; i--){
+            rString += str[i];
+        }
+        return rString;
     }
 
-    // @return string with identical contents, in reverse order, with first character capitalized
-    reverseThenCamelCase(str){
-        return null;
+
+
+    //reverse each word in a string
+    reverseWords(str){
+        let rWordString = "";
+        let rWords = "";
+        for(let i = str.length-1; i >=0; i--){
+            if (str[i] === " "){
+                rWordString = " " + rWords + rWordString;
+                rWords = "";
+            }else {rWords += str[i]}
+
+        }
+        return rWords + rWordString;
     }
 
+
+//@return string with identical contents, in reverse order, with first character capitalized
+
+    reverseThenCamelCase(str){
+        let rString = this.reverseString(str);
+        let reverseString = rString;
+        reverseString = this.camelCase(rString);
+
+        return reverseString;
+    }
+
     // @return string with identical contents excluding first and last character
     removeFirstAndLastCharacter(str){
-        return null;
+        let newString = "";
+        for (let i=1; i<str.length-1; i++){
+            newString += str[i];
+        }
+        return newString;
     }
 
     // @return string with identical characters, each with opposite casing
     invertCasing(str){
-        return null;
+        let charCase = [];
+        let inverseString = "";
+        for(let i=0; i<=str.length-1;i++){
+            charCase += str[i];
+        if(charCase[i] === charCase[i].toUpperCase()){
+            inverseString += charCase[i].toLowerCase();
+         }else {inverseString += charCase[i].toUpperCase();
+         }    
+    }
+        return inverseString;
     }
 }
 

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(input);
 
     expect(actual).toEqual(expected);
 });
@@ -19,7 +19,7 @@ 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);
 });
@@ -30,7 +30,7 @@ test("reverseWordsTest", () => {
     let input = "she sells sea shells";
     let expected = "ehs slles aes sllehs";
 
-    let actual = stringsAndTings.camelCase(15);
+    let actual = stringsAndTings.reverseWords(input);
 
     expect(actual).toEqual(expected);
 });
@@ -41,7 +41,7 @@ test("reverseThenCamelCaseTest", () => {
     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 +52,7 @@ 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);
 });
@@ -64,7 +64,7 @@ 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);
 });