create-lwc-plugin/template-primitive/src/helpers/assertions.ts

Wizard-like CLI tool for scaffolding a new plugin for Lightweight Charts™

/**
 * Ensures that value is defined.
 * Throws if the value is undefined, returns the original value otherwise.
 *
 * @param value - The value, or undefined.
 * @returns The passed value, if it is not undefined
 */
export function ensureDefined(value: undefined): never;
export function ensureDefined<T>(value: T | undefined): T;
export function ensureDefined<T>(value: T | undefined): T {
	if (value === undefined) {
		throw new Error('Value is undefined');
	}

	return value;
}

/**
 * Ensures that value is not null.
 * Throws if the value is null, returns the original value otherwise.
 *
 * @param value - The value, or null.
 * @returns The passed value, if it is not null
 */
export function ensureNotNull(value: null): never;
export function ensureNotNull<T>(value: T | null): T;
export function ensureNotNull<T>(value: T | null): T {
	if (value === null) {
		throw new Error('Value is null');
	}

	return value;
}