Add checker() function that returns a named checker

README.md

@@ -515,6 +515,8 @@ Please see (CONTRIBUTING.md)
 
 ## Changelog
 
+- 4.5.0
+  - Add `checker()` function to return the boolean checker function itself.
 - 4.4.0
   - Add `json` checker to check for JSON-friendly values (null, true, false, finite numbers, strings, plain objects, plain arrays)
 - 4.3.0

lib/classes/Blorker.js

@@ -63,6 +63,23 @@ class Blorker {
 		this._find = this._find.bind(this);
 	}
 
+	/**
+	 * Return a specific checker.
+	 * @param {string|Function|Array|Object} type A single stringy type reference (e.g. 'str'), functional shorthand type reference (e.g. `String`), or an object/array with list of types (e.g. `{name:'str'}` or `['str', 'num']`).
+	 * @return {function} The specified checker or undefined if it doesn't exist.
+	 */
+	checker(type) {
+		// Check args.
+		runChecker(this._checkers.string, type, "arguments[0]", BlorkError);
+
+		// Return the checker.
+		const checker = this._checkers[type];
+		if (checker) return checker;
+
+		// Not found.
+		throwError(BlorkError, "Checker not found", type, "arguments[0]");
+	}
+
 	/**
 	 * Check values against types.
 	 * Throws an error if a value doesn't match a specified type.

lib/exports.js

@@ -6,13 +6,14 @@ const format = require("./functions/format");
 const { ANY } = require("./constants");
 
 // Make a default instance.
-const { args, check, add, throws } = blork();
+const { args, check, add, checker, throws } = blork();
 
 // Exports.
 exports.blork = blork;
 exports.args = args;
 exports.check = check;
 exports.add = add;
+exports.checker = checker;
 exports.throws = throws;
 exports.format = format;
 exports.debug = debug;

lib/functions/blork.js

@@ -17,7 +17,8 @@ module.exports = function blork() {
 	return {
 		check: blorker.check.bind(blorker),
 		args: blorker.args.bind(blorker),
-		throws: blorker.throws.bind(blorker),
-		add: blorker.add.bind(blorker)
+		add: blorker.add.bind(blorker),
+		checker: blorker.checker.bind(blorker),
+		throws: blorker.throws.bind(blorker)
 	};
 };

test/exports.checker.test.js

@@ -0,0 +1,17 @@
+const BlorkError = require("../lib/errors/BlorkError");
+const { checker } = require("../lib/exports");
+
+// Tests.
+describe("exports.check()", () => {
+	test("Getting and using a checker works correctly", () => {
+		expect(checker("string")("abc")).toBe(true);
+		expect(checker("string")(123)).toBe(false);
+	});
+	test("Throw BlorkError if passing a non-string", () => {
+		expect(() => checker(123)).toThrow(BlorkError);
+		expect(() => checker(false)).toThrow(BlorkError);
+	});
+	test("Throw BlorkError if asking for non-existant checker", () => {
+		expect(() => checker("abc")).toThrow(BlorkError);
+	});
+});