test Archives | JS FAQ - JavaScript Guides Online

Home » test

How to test pure functions with Jest

Unit Testing: Jestjest, logic, pure function, test

Test cases for pure functions focus on verifying consistent outputs for given inputs without side effects. Use toEqual for deep equality, toThrow for error handling, and toBeCloseTo for floating-point precision. Group tests with describe blocks for better organization and maintainability.

Standard Objects: RegExp

How to test a string with a regular expression in JavaScript

Standard Objects: RegExpboolean, js regexp, regexp, test

Common regex pitfalls: escaping special characters in new RegExp(), multiline 'm' flag for anchors ^ and $, character set rules for hyphen and negation, and catastrophic backtracking from nested quantifiers. Understanding these regex bugs prevents performance issues and invalid pattern errors.