feat: add string.isbn keyword for ISBN validation

ark/type/__tests__/integration/allConfig.ts

@@ -116,6 +116,9 @@ configure({
 		"string.creditCard": {
 			description: "configured"
 		},
+		"string.isbn": {
+			description: "configured"
+		},
 		"string.date.parse": {
 			description: "configured"
 		},

ark/type/__tests__/keywords/string.test.ts

@@ -88,6 +88,44 @@ contextualize(() => {
 		).snap('must be a credit card number (was "5489582921773370")')
 	})
 
+	it("isbn", () => {
+		const Isbn = type("string.isbn")
+		// ISBN-10
+		attest(Isbn("4873118735")).equals("4873118735")
+		attest(Isbn("4-87311-873-5")).equals("4-87311-873-5")
+		attest(Isbn("4 87311 873 5")).equals("4 87311 873 5")
+		attest(Isbn("020530902X")).equals("020530902X")
+		attest(Isbn("0-205-30902-X")).equals("0-205-30902-X")
+		// ISBN-13
+		attest(Isbn("9784873118734")).equals("9784873118734")
+		attest(Isbn("978-4-87311-873-4")).equals("978-4-87311-873-4")
+		attest(Isbn("9790000000001")).equals("9790000000001")
+		// Invalid checksum
+		attest(Isbn("4873118736").toString()).equals(
+			'must be an ISBN (was "4873118736")'
+		)
+		attest(Isbn("9784873118735").toString()).equals(
+			'must be an ISBN (was "9784873118735")'
+		)
+		// Lowercase x is not accepted
+		attest(Isbn("020530902x").toString()).equals(
+			'must be an ISBN (was "020530902x")'
+		)
+		// X in wrong position
+		attest(Isbn("X234567890").toString()).equals(
+			'must be an ISBN (was "X234567890")'
+		)
+		// Wrong length
+		attest(Isbn("978487311873").toString()).equals(
+			'must be an ISBN (was "978487311873")'
+		)
+		// Non-digit characters
+		attest(Isbn("abc1234567890").toString()).equals(
+			'must be an ISBN (was "abc1234567890")'
+		)
+		attest(Isbn("").toString()).equals('must be an ISBN (was "")')
+	})
+
 	it("semver", () => {
 		attest(keywords.string.semver("1.0.0")).snap("1.0.0")
 		attest(keywords.string.semver("-1.0.0").toString()).snap(

ark/type/keywords/string.ts

@@ -170,6 +170,44 @@ export const creditCard = rootSchema({
 	}
 })
 
+// https://en.wikipedia.org/wiki/ISBN#ISBN-10_check_digits
+export const isIsbn10 = (input: string): boolean => {
+	let sum = 0
+	for (let i = 0; i < 10; i++) {
+		const char = input[i]
+		const value = char === "X" ? 10 : Number.parseInt(char, 10)
+		sum += value * (10 - i)
+	}
+	return sum % 11 === 0
+}
+
+// https://en.wikipedia.org/wiki/ISBN#ISBN-13_check_digit_calculation
+export const isIsbn13 = (input: string): boolean => {
+	let sum = 0
+	for (let i = 0; i < 13; i++) {
+		const value = Number.parseInt(input[i], 10)
+		sum += value * (i % 2 === 0 ? 1 : 3)
+	}
+	return sum % 10 === 0
+}
+
+const isbnSeparatorMatcher = /[ -]+/g
+const isbn10Matcher = /^\d{9}[\dX]$/
+const isbn13Matcher = /^\d{13}$/
+
+export const isbn = rootSchema({
+	domain: "string",
+	predicate: {
+		meta: "an ISBN",
+		predicate: (input: string) => {
+			const sanitized = input.replace(isbnSeparatorMatcher, "")
+			if (isbn10Matcher.test(sanitized)) return isIsbn10(sanitized)
+			if (isbn13Matcher.test(sanitized)) return isIsbn13(sanitized)
+			return false
+		}
+	}
+})
+
 type DayDelimiter = "." | "/" | "-"
 
 const dayDelimiterMatcher = /^[./-]$/
@@ -919,6 +957,7 @@ export const string = Scope.module(
 		email,
 		integer: stringInteger,
 		ip,
+		isbn,
 		json,
 		lower,
 		normalize,
@@ -953,6 +992,7 @@ export declare namespace string {
 		email: string
 		integer: stringInteger.submodule
 		ip: ip.submodule
+		isbn: string
 		json: stringJson.submodule
 		lower: lower.submodule
 		normalize: normalize.submodule