override

The createOverride() function lets you register changes (default values and/or methods) that will be applied when creating an object.

The typical pattern is:

1. create the base object
2. call overrideHandler.apply(self) just before returning it
3. from another module, register overrides via setPropertyDefaultValue / setMethod

This tool is heavily used in dataParser to add/alter capabilities without modifying the parser implementation.

WARNING

Overrides are stored in a global store (valid throughout the process): the last override applied to the same property/method wins.

Interactive example

Syntax

interface OverrideHandler<
	GenericInterface extends object
> {
	setMethod<
		GenericProperty extends keyof GenericInterface
	>(
		prop: GenericProperty,
		theFunction: (
			self: GenericInterface,
			...args: any[]
		) => any
	): void;

	setPropertyDefaultValue<
		GenericProperty extends keyof GenericInterface
	>(
		prop: GenericProperty,
		value: any
	): void;

	apply(overrideInterface: GenericInterface): GenericInterface;
}

function createOverride<
	GenericInterface extends object
>(overrideName: string): OverrideHandler<GenericInterface>;

Usage notes

• overrideName : choose a unique name (often a namespaced id like @duplojs/utils/...).
• apply(self) : applies overrides and returns a new self object (with wrapped methods to receive the correct self).
• setMethod(...) : the function receives self as the first parameter, which avoids this issues and allows referencing overridden properties.
• setPropertyDefaultValue(...) : sets a value applied at creation (and can overwrite an existing value).

See also

• builder - Similar “declare then configure” pattern
• globalStore - Global per-process storage