expand() context types do not allow undefined values even though the code implementation does

[msheakoski]

I noticed when updating to v3 and using the package's internal types, undefined values passed to expand() result in an error. The current types do not reflect the actual behavior of the JavaScript code, which accepts null and undefined and converts it to an empty string (see test below). Updating the PrimitiveValue type to include undefined would fix this issue:

// proposed fix
export type PrimitiveValue = string | number | boolean | null | undefined;

url-template/lib/url-template.d.ts

Lines 1 to 5 in ee27eb9

	export type PrimitiveValue = string | number | boolean | null;
	export interface Template {
	expand(context: Record<string, PrimitiveValue | PrimitiveValue[] | Record<string, PrimitiveValue | PrimitiveValue[]>>): string;
	}

url-template/test/url-template-test.js

Lines 74 to 77 in ee27eb9

	test('expand variables that are undefined or null', () => {
	assert('{undef}', '');
	assert('{null}', '');
	});

[msheakoski]

For anybody who needs a quick fix until the types are updated, you can override the types that this package uses locally:

Create a file such as mytypes/url-template.d.ts:

// These custom types are needed until https://github.com/bramstein/url-template/issues/79 is resolved.

declare module "url-template" {
  export type PrimitiveValue = string | number | boolean | null | undefined

  export interface Template {
    expand(context: Record<string, PrimitiveValue | PrimitiveValue[] | Record<string, PrimitiveValue | PrimitiveValue[]>>): string
  }

  export function parseTemplate(template: string): Template
}

Update tsconfig.json:

{
  // add or modify this line
  "include": "./mytypes/**/*", "any/other/type/files/you/use.d.ts"
}