Explores the difference between optional parameters and undefined types in TypeScript, with practical examples from React Query.
A guide to fixing the common React error 'Cannot read property of undefined', covering how to read stack traces and properly initialize state.
Explains three methods to check if a variable is defined in JavaScript, covering typeof, try-catch, and global object checks.
A comprehensive guide to the null value in JavaScript, covering its meaning, detection, differences from undefined, and usage pitfalls.
Explains the void operator in JavaScript and the void type in TypeScript, highlighting their differences and common use cases.
A guide explaining what 'undefined' is in JavaScript, detailing common scenarios that create it, and offering practical tips to handle it effectively.
