feat: Add path, relative, absolute checkers for validating filesystem…

… paths

README.md

@@ -271,6 +271,9 @@ This section lists all types that are available in Blork. Types are strings made
 | `kebab`, `slug`                  | kebab-case strings e.g. URL slugs (non-empty alphanumeric lowercase)
 | `train`                          | Train-Case strings e.g. HTTP-Headers (non-empty with uppercase first letters)
 | `identifier`                     | JavaScript identifier names (string starting with **_**, **$**, or letter)
+| `path`                           | Valid filesystem path (e.g. "abc/def")
+| `absolute`, `abs`                | Valid absolute path (e.g. "/abc/def" or "C:\abd\def")
+| `relative`, `rel`                | Valid relative path (e.g. "../abc/def" or "..\abd\def")
 | `function`, `func`               | Functions (using **instanceof Function**)
 | `object`, `obj`                  | Plain objects (using **typeof && !null** and constructor check)
 | `objectlike`                     | Any object (using **typeof && !null**)

lib/checkers/checkers.js

@@ -9,13 +9,14 @@ const R_ALPHABETIC = /^[a-zA-Z]+$/;
 const R_NUMERIC = /^[0-9]+$/;
 const R_UPPER = /^[A-Z]+$/;
 const R_LOWER = /^[a-z]+$/;
-const R_CAMEL = /^[a-z][a-zA-Z0-9]*$/;
-const R_PASCAL = /^[A-Z][a-zA-Z0-9]*$/;
-const R_SNAKE = /^[a-z][a-z0-9]*(_[a-z0-9]+)*$/;
-const R_SCREAMING = /^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$/;
-const R_KEBAB = /^[a-z][a-z0-9]*(-[a-z0-9]+)*$/;
-const R_TRAIN = /^[A-Z][a-zA-Z0-9]*(-[A-Z0-9][a-zA-Z0-9]+)*$/;
+const R_CAMEL = /^[a-z][a-zA-Z0-9]*$/; // e.g. myVarName
+const R_PASCAL = /^[A-Z][a-zA-Z0-9]*$/; // e.g. MyVarName
+const R_SNAKE = /^[a-z][a-z0-9]*(_[a-z0-9]+)*$/; // e.g. my_var_name
+const R_SCREAMING = /^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$/; // e.g. MY_VAR_NAME
+const R_KEBAB = /^[a-z][a-z0-9]*(-[a-z0-9]+)*$/; // e.g. my-var-name
+const R_TRAIN = /^[A-Z][a-zA-Z0-9]*(-[A-Z0-9][a-zA-Z0-9]+)*$/; // e.g. My-Var-Name
 const R_IDENTIFIER = /^[$a-zA-Z_][a-zA-Z0-9_$]*$/;
+const R_ABSOLUTE = /^(?:\/|[a-zA-Z]:\\|[/\\]{2}[^/\\]+[/\\/]+[^/\\]+)()/; // e.g. "/" (Unix) "C:\" (Windows) or "//server/file" or "\\server\file" (UNC)
 
 // Checkers.
 function isNull(v) { return v === null; }
@@ -54,6 +55,9 @@ function isScreaming(v) { return typeof v === "string" && R_SCREAMING.test(v); }
 function isKebab(v) { return typeof v === "string" && R_KEBAB.test(v); }
 function isTrain(v) { return typeof v === "string" && R_TRAIN.test(v); }
 function isIdentifier(v) { return typeof v === "string" && R_IDENTIFIER.test(v); }
+function isPath(v) { return typeof v === "string" && v.length > 0 && v.length <= 260 && v.indexOf(String.fromCharCode(0)) === -1; } // Total length is no more than 260 (Windows), doesn't contain NUL (Windows and Unix).
+function isAbsolute(v) { return isPath(v) && R_ABSOLUTE.test(v); }
+function isRelative(v) { return isPath(v) && !R_ABSOLUTE.test(v); }
 function isPrimitive(v) { return v === undefined || v === null || typeof v === "boolean" || typeof v === "string" || Number.isFinite(v); }
 function isFunction(v) { return typeof v === "function"; }
 function isObject(v) { return typeof v === "object" && v !== null; }
@@ -117,6 +121,9 @@ isScreaming.desc = "SCREAMING_SNAKE_CASE string";
 isKebab.desc = "kebab-case string";
 isTrain.desc = "Camel-Kebab-Case string";
 isIdentifier.desc = "valid JavaScript identifier";
+isPath.desc = "valid path";
+isAbsolute.desc = "absolute path";
+isRelative.desc = "relative path";
 isFunction.desc = "function";
 isObject.desc = "object";
 isPlainObject.desc = "plain object";
@@ -206,6 +213,11 @@ const checkers = {
 	"slug": isKebab,
 	"train": isTrain,
 	"identifier": isIdentifier,
+	"path": isPath,
+	"abs": isAbsolute,
+	"absolute": isAbsolute,
+	"rel": isRelative,
+	"relative": isRelative,
 
 	// Objects.
 	"function": isFunction,

test/checkers/checkers.test.js

@@ -77,6 +77,11 @@ describe("checkers", () => {
 		expect(mockCheck("my-var", "slug")).toBe(undefined);
 		expect(mockCheck("My-Var", "train")).toBe(undefined);
 		expect(mockCheck("$name", "identifier")).toBe(undefined);
+		expect(mockCheck("abc/def", "path")).toBe(undefined);
+		expect(mockCheck("..\\abc\\def", "rel")).toBe(undefined);
+		expect(mockCheck("../abc/def", "relative")).toBe(undefined);
+		expect(mockCheck("/abc/def", "abs")).toBe(undefined);
+		expect(mockCheck("C:\\abc\\def", "absolute")).toBe(undefined);
 
 		// Objects.
 		expect(mockCheck(function() {}, "function")).toBe(undefined);
@@ -195,6 +200,11 @@ describe("checkers", () => {
 		expect(() => mockCheck("my-VAR", "slug")).toThrow(TypeError);
 		expect(() => mockCheck("my-var", "train")).toThrow(TypeError);
 		expect(() => mockCheck("*name", "identifier")).toThrow(TypeError);
+		expect(() => mockCheck(String.fromCharCode(0), "path")).toThrow(TypeError);
+		expect(() => mockCheck("/abc/def", "rel")).toThrow(TypeError);
+		expect(() => mockCheck("C:\\abc\\def", "relative")).toThrow(TypeError);
+		expect(() => mockCheck("../abc/def", "abs")).toThrow(TypeError);
+		expect(() => mockCheck("..\\abc\\def", "absolute")).toThrow(TypeError);
 
 		// Objects.
 		expect(() => mockCheck({}, "function")).toThrow(TypeError);