Alias for checkNotUndefined
Shorthand notation for converting an unexpected null/undefined reference to a more telling error message.
E.g
const mapElement = checkNotNull(document.getElementById('map'), 'Missing #map element in DOM');
will result in a strongly-typed HTMLElement which cannot be null, or throw an Error with a dedicated message
(rather than simply crashing with a null-pointer reference when used later).
An object of a union type including null and undefined.
An optional message to throw as Error message.
A non-null object
Alias for isNotUndefined
A type guard which uses generics to narrow a "type or null or undefined" to "type".
This is particularly useful with RxJs filter, as it recognizes the narrowing and infers the type of the resulting stream.
Alias for undefinedSafe
Converts the given function to a new function which calls through to the original function except if the input is
undefined, in which case the function returns undefined. In other words, it wraps a function to guard it against
undefined input.
Returns a trimmed string, or undefined if the string ends up empty.
Returns a trimmed string, converting undefined to an empty string.
Converts the given function to a new function which calls through to the original function except if the input is
undefined, in which case the function returns undefined. In other words, it wraps a function to guard it against
undefined input.
Converts the given function to a new function which calls through to the original function except if the input is
undefined, in which case the function returns undefined. In other words, it wraps a function to guard it against
undefined input.
This module contains functions to fail-fast on null/undefined, and do various type guards and narrowing in TypeScript.