JavaScript: Check if a given string is upper case or not

JavaScript fundamental (ES6 Syntax): Exercise-184 with Solution

Check String Uppercase

Write a JavaScript program to check if a given string is upper case or not.

• Convert the given string to upper case, using String.prototype.toUpperCase() and compare it to the original.

Sample Solution:

JavaScript Code:

// Define a function 'isUpperCase' that checks if all characters in a string 'str' are uppercase
const isUpperCase = str => str === str.toUpperCase();

// Test cases to check if the provided strings contain only uppercase characters
console.log(isUpperCase('ABC')); // true (all characters are uppercase)
console.log(isUpperCase('A3@$')); // true (all characters are uppercase)
console.log(isUpperCase('aB4')); // false (contains lowercase characters)

Output:

true
true
false

Visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-184-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that determines if an entire string is in uppercase by comparing it to its uppercase version.
• Write a JavaScript function that tests a string and returns true if all alphabetic characters are uppercase.
• Write a JavaScript program that ignores non-letter characters and checks if the remaining letters are all in uppercase.
• Write a JavaScript function that converts a string to uppercase and then compares it with the original to determine its case.

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