chore(ts): improve thirdParty.allow typings

src/index.d.ts

@@ -216,42 +216,60 @@ export type ThirdPartyOutput = string | ((dependencies: Dependency[]) => void) |
  template?: ((dependencies: Dependency[]) => string) | string,
 };
 
+/**
+ * SPDX Licence Identifier.
+ */
+type SpdxId = string;
+
+/**
+ * Function checking dependency license validity.
+ */
+type ThirdPartyDependencyValidatorFn = (Dependency: Dependency) => boolean;
+
+type ThirdPartyValidator = SpdxId | ThirdPartyDependencyValidatorFn;
+
+interface ThirdPartyAllowOptions {
+ /**
+ * Testing if the license if valid
+ */
+ test: ThirdPartyValidator;
+
+ /**
+ * Fail if a dependency does not specify any licenses
+ * @default false
+ */
+ failOnUnlicensed?: boolean;
+
+ /**
+ * Fail if a dependency specify a license that does not match given requirement
+ * @default false
+ */
+ failOnViolation?: boolean;
+}
+
 export type ThirdParty = ((dependencies: Dependency[]) => void) | {
  /**
- * If private dependencies should be allowed (`private: true` in package.json)
+ * If private dependencies should be checked (`private: true` in package.json)
  * @default false
  */
  includePrivate?: boolean,
 
  /**
  * Ensures that dependencies does not violate any license restriction.
+ *
  * For example, suppose you want to limit dependencies with MIT or Apache-2.0
- * licenses, simply define the restriction such as:
+ * licenses, simply define the restriction:
+ *
  * @example
- * {allow: '(MIT OR Apache-2.0)'}
+ * {
+ * allow: '(MIT OR Apache-2.0)'
+ * }
  *
- * allow(dependency) {
- * return dependency.license === 'MIT';
- * }
- */
- allow?: string | ((dependency: Dependency) => boolean) | {
- /**
- * Testing if the license if valid
- */
- test: string | ((dependency: Dependency) => boolean),
-
- /**
- * Fail if a dependency does not specify any licenses
- * @default false
- */
- failOnUnlicensed?: boolean,
-
- /**
- * Fail if a dependency specify a license that does not match given requirement
- * @default false
- */
- failOnViolation?: boolean,
- },
+ * allow(dependency) {
+ * return dependency.license === 'MIT';
+ * }
+ */
+ allow?: ThirdPartyValidator | ThirdPartyAllowOptions,
 
  /**
  * Output file for