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

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

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:

//#Source https://bit.ly/2neWfJ2 
const isUpperCase = str => str === str.toUpperCase();
console.log(isUpperCase('ABC')); 
console.log(isUpperCase('[email protected]$'));
console.log(isUpperCase('aB4'));

Sample Output:

true
true
false

Pictorial Presentation:

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

Flowchart:

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

Live Demo:

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


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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv