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JavaScript: Count the number of vowels in a given string

JavaScript validation with regular expression: Exercise-8 with Solution

Write a JavaScript function to count the number of vowels in a given string.

Test Data:
console.log(alphabetize_string('United States'));
Output :
"SUadeeinsttt"

Pictorial Presentation:

JavaScript: Count the number of vowels in a given string

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>Write a JavaScript function to count the number of vowels in a given string</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function vowel_count(str) {

  return str.match(/[aeiou]/gi).length;

}

console.log(vowel_count('The quick brown fox jumps over the lazy dog'));

Sample Output:

11

Flowchart:

Flowchart: JavaScript- Count the number of vowels in a given string

Live Demo:

See the Pen javascript-regexp-exercise-8 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

JavaScript: Delete operator

const name = 'Owen';
age = 21;

console.log(delete name);
console.log(delete age);

The delete operator returns a boolean value: true on a successful deletion, else it'll return false. However, variables declared with the var, const or let keyword cannot be deleted using the delete operator.
The name variable was declared with a const keyword, so its deletion is not successful: false is returned. When we set age equal to 21, we actually added a property called age to the global object. You can successfully delete properties from objects this way, also the global object, so delete age returns true.

Ref: https://bit.ly/323Y0P6