Add validateOptions, oneOf, forbidden, isBuffer

index.js

@@ -3,9 +3,16 @@
 const createError = require("create-error");
 const assureArray = require("assure-array");
 const defaultValue = require("default-value");
+const util = require("util");
 
 let ValidationError = createError("ValidationError", { path: [] });
 
+function allowExtraProperties (rules) {
+	return function (value) {
+		return validateObject(value, rules, true);
+	};
+}
+
 function validateValue(value, argRules) {
 	let argRules_ = assureArray(argRules);
 	let isRequired = argRules_.some((rule) => rule.___validationMarker === "required");
@@ -21,6 +28,7 @@ function validateValue(value, argRules) {
 
 		for (let rule of actualRules) {
 			if (typeof rule === "object") {
+				/* FIXME: Check that this isn't an array, Date, Buffer, ... */
 				errors = validateObject(value, rule);
 			} else {
 				try {
@@ -125,17 +133,24 @@ function aggregrateErrors(errors) {
 	}
 }
 
-module.exports = {
-	validateArguments: function (args, rules) {
+function validateArguments(args, rules) {
 	let errors = validateArgumentList(args, rules);
 
 		aggregrateErrors(errors);
-	},
+}
+
+module.exports = {
+	validateArguments: validateArguments,
 	validateValue: function (value, rules) {
 		let errors = validateValue(value, assureArray(rules));
 
 		aggregrateErrors(errors);
 	},
+	validateOptions: function (args, optionsRules) {
+		return validateArguments(args, [
+			["options", optionsRules]
+		]);
+	},
 	ValidationError: ValidationError,
 	required: {___validationMarker: "required"},
 	isFunction: function (value) {
@@ -163,6 +178,11 @@ module.exports = {
 			throw new ValidationError("Must be a Date object");
 		}
 	},
+	isBuffer: function (value) {
+		if (!(value instanceof Buffer)) {
+			throw new ValidationError("Must be a Buffer object");
+		}
+	},
 	either: function (...alternatives) {
 		if (alternatives.length === 0) {
 			throw new Error("Must specify at least one alternative");
@@ -189,6 +209,9 @@ module.exports = {
 		}
 	},
 	when: function (predicate, rules) {
+		if (rules == null) {
+			throw new Error("No rules specified for a `when` validation clause; did you misplace a parenthese?");
+		} else {
 			let rules_ = assureArray(rules).map((rule) => {
 				if (typeof rule === "object") {
 					/* We automatically allow extraneous properties in a `when` clause, because it'll generally be used as a partial addition to an otherwise-fully-specified object structure. */
@@ -207,6 +230,7 @@ module.exports = {
 					return [];
 				}
 			};
+		}
 	},
 	matchesFormat: function (regex) {
 		return function (value) {
@@ -215,6 +239,19 @@ module.exports = {
 			}
 		};
 	},
+	oneOf: function (validValues) {
+		if (Array.isArray(validValues)) {
+			let validValueSet = new Set(validValues);
+	
+			return function (value) {
+				if (!validValueSet.has(value)) {
+					throw new ValidationError(`Must be one of: ${validValues.map((item) => util.inspect(item)).join(", ")}`);
+				}
+			}
+		} else {
+			throw new Error("Argument to `oneOf` must be an array of values");
+		}
+	},
 	arrayOf: function (rules) {
 		let rules_ = assureArray(rules);
 
@@ -256,9 +293,10 @@ module.exports = {
 			}
 		};
 	},
-	allowExtraProperties: function (rules) {
-		return function (value) {
-			return validateObject(value, rules, true);
-		};
+	allowExtraProperties: allowExtraProperties,
+	forbidden: function (value) {
+		if (value != null) {
+			throw new ValidationError("Value exists in a place that should be empty");
+		}
 	}
 };