str reverse javascript code example
Example 1: javascript reverse string
function reverseString(str) {
// Step 1. Create an empty string that will host the new created string
var newString = "";
// Step 2. Create the FOR loop
/* The starting point of the loop will be (str.length - 1) which corresponds to the
last character of the string, "o"
As long as i is greater than or equals 0, the loop will go on
We decrement i after each iteration */
for (var i = str.length - 1; i >= 0; i--) {
newString += str[i]; // or newString = newString + str[i];
}
/* Here hello's length equals 5
For each iteration: i = str.length - 1 and newString = newString + str[i]
First iteration: i = 5 - 1 = 4, newString = "" + "o" = "o"
Second iteration: i = 4 - 1 = 3, newString = "o" + "l" = "ol"
Third iteration: i = 3 - 1 = 2, newString = "ol" + "l" = "oll"
Fourth iteration: i = 2 - 1 = 1, newString = "oll" + "e" = "olle"
Fifth iteration: i = 1 - 1 = 0, newString = "olle" + "h" = "olleh"
End of the FOR Loop*/
// Step 3. Return the reversed string
return newString; // "olleh"
}
reverseString('hello');
Example 2: reverse a word javascript
function reverseWords(str) {
const allWords = str.split(" ")
return allWords.map(item => item.split("").reverse().join("")).join(" ")
}