isEmptyOrWhitespace
Checks if a string is empty or consists only of whitespace characters.
1/**
2 * Checks if a string is empty or consists only of whitespace characters.
3 *
4 * @param str - The string to check.
5 * @returns True if the string is empty or only whitespace.
6 */
7export function isEmptyOrWhitespace(str: string): boolean {
8 return typeof str === 'string' && str.trim().length === 0;
9}Simple and Efficient
Uses
trim().lengthto quickly determine if a string is effectively empty without manual iteration or regex.Type Safety Guard
Ensures the input is a string before performing operations, preventing runtime errors from invalid types.
Whitespace-Aware
Accurately detects strings that visually appear empty but contain spaces, tabs, or newlines.
Minimal Footprint
Extremely lightweight, making it ideal for frequent use in input validation without performance impact.
Tests | Examples
1test('returns true for empty string', () => {
2 expect(isEmptyOrWhitespace('')).toBe(true);
3});
4
5test('returns true for whitespace-only strings', () => {
6 expect(isEmptyOrWhitespace(' ')).toBe(true);
7 expect(isEmptyOrWhitespace('
8 ')).toBe(true);
9});
10
11test('returns false for non-empty strings', () => {
12 expect(isEmptyOrWhitespace('hello')).toBe(false);
13 expect(isEmptyOrWhitespace(' hi ')).toBe(false);
14});
15
16test('returns false for non-string input', () => {
17 expect(isEmptyOrWhitespace(null as any)).toBe(false);
18 expect(isEmptyOrWhitespace(undefined as any)).toBe(false);
19 expect(isEmptyOrWhitespace(123 as any)).toBe(false);
20});Common Use Cases
Form Validation
Prevent users from submitting forms with only whitespace in required text fields.
Sanitizing User Input
Detect and handle meaningless input before processing or storing it.
Conditional Rendering or Display
Avoid rendering labels, messages, or content placeholders when strings are blank or just whitespace.
Preprocessing Text Data
Filter out empty or irrelevant entries when cleaning raw text data from files or user submissions.