1 files changed, 152 insertions, 0 deletions
diff --git a/src/modules/commerce/index.ts b/src/modules/commerce/index.ts
index f0068415..2464af03 100644
--- a/src/modules/commerce/index.ts
+++ b/src/modules/commerce/index.ts
@@ -2,6 +2,79 @@ import type { Faker } from '../../faker';
 import { bindThisToMemberFunctions } from '../../internal/bind-this-to-member-functions';
 import { deprecated } from '../../internal/deprecated';
 
+// Source for official prefixes: https://www.isbn-international.org/range_file_generation
+const ISBN_LENGTH_RULES: Record<
+  string,
+  Array<[rangeMaximum: number, length: number]>
+> = {
+  '0': [
+    [1999999, 2],
+    [2279999, 3],
+    [2289999, 4],
+    [3689999, 3],
+    [3699999, 4],
+    [6389999, 3],
+    [6397999, 4],
+    [6399999, 7],
+    [6449999, 3],
+    [6459999, 7],
+    [6479999, 3],
+    [6489999, 7],
+    [6549999, 3],
+    [6559999, 4],
+    [6999999, 3],
+    [8499999, 4],
+    [8999999, 5],
+    [9499999, 6],
+    [9999999, 7],
+  ],
+  '1': [
+    [99999, 3],
+    [299999, 2],
+    [349999, 3],
+    [399999, 4],
+    [499999, 3],
+    [699999, 2],
+    [999999, 4],
+    [3979999, 3],
+    [5499999, 4],
+    [6499999, 5],
+    [6799999, 4],
+    [6859999, 5],
+    [7139999, 4],
+    [7169999, 3],
+    [7319999, 4],
+    [7399999, 7],
+    [7749999, 5],
+    [7753999, 7],
+    [7763999, 5],
+    [7764999, 7],
+    [7769999, 5],
+    [7782999, 7],
+    [7899999, 5],
+    [7999999, 4],
+    [8004999, 5],
+    [8049999, 5],
+    [8379999, 5],
+    [8384999, 7],
+    [8671999, 5],
+    [8675999, 4],
+    [8697999, 5],
+    [9159999, 6],
+    [9165059, 7],
+    [9168699, 6],
+    [9169079, 7],
+    [9195999, 6],
+    [9196549, 7],
+    [9729999, 6],
+    [9877999, 4],
+    [9911499, 6],
+    [9911999, 7],
+    [9989899, 6],
+    [9999999, 7],
+  ],
+};
+
 /**
  * Module to generate commerce and product related entries.
  *
@@ -258,4 +331,83 @@ export class CommerceModule {
       this.faker.definitions.commerce.product_description
     );
   }
+
+  /**
+   * Returns a random [ISBN](https://en.wikipedia.org/wiki/ISBN) identifier.
+   *
+   * @param options The variant to return or an options object. Defaults to `{}`.
+   * @param options.variant The variant to return. Can be either `10` (10-digit format)
+   * or `13` (13-digit format). Defaults to `13`.
+   * @param options.separator The separator to use in the format. Defaults to `'-'`.
+   *
+   * @example
+   * faker.commerce.isbn() // '978-0-692-82459-7'
+   * faker.commerce.isbn(10) // '1-155-36404-X'
+   * faker.commerce.isbn(13) // '978-1-60808-867-6'
+   * faker.commerce.isbn({ separator: ' ' }) // '978 0 452 81498 1'
+   * faker.commerce.isbn({ variant: 10, separator: ' ' }) // '0 940319 49 7'
+   * faker.commerce.isbn({ variant: 13, separator: ' ' }) // '978 1 6618 9122 0'
+   *
+   * @since 8.1.0
+   */
+  isbn(
+    options:
+      | 10
+      | 13
+      | {
+          /**
+           * The variant of the identifier to return.
+           * Can be either `10` (10-digit format)
+           * or `13` (13-digit format).
+           *
+           * @default 13
+           */
+          variant?: 10 | 13;
+
+          /**
+           * The separator to use in the format.
+           *
+           * @default '-'
+           */
+          separator?: string;
+        } = {}
+  ): string {
+    if (typeof options === 'number') {
+      options = { variant: options };
+    }
+
+    const { variant = 13, separator = '-' } = options;
+
+    const prefix = '978';
+    const [group, groupRules] =
+      this.faker.helpers.objectEntry(ISBN_LENGTH_RULES);
+    const element = this.faker.string.numeric(8);
+    const elementValue = parseInt(element.slice(0, -1));
+
+    const registrantLength = groupRules.find(
+      ([rangeMaximum]) => elementValue <= rangeMaximum
+    )[1];
+
+    const registrant = element.slice(0, registrantLength);
+    const publication = element.slice(registrantLength);
+
+    const data = [prefix, group, registrant, publication];
+    if (variant === 10) {
+      data.shift();
+    }
+
+    const isbn = data.join('');
+
+    let checksum = 0;
+    for (let i = 0; i < variant - 1; i++) {
+      const weight = variant === 10 ? i + 1 : i % 2 ? 3 : 1;
+      checksum += weight * parseInt(isbn[i]);
+    }
+
+    checksum = variant === 10 ? checksum % 11 : (10 - (checksum % 10)) % 10;
+
+    data.push(checksum === 10 ? 'X' : checksum.toString());
+
+    return data.join(separator);
+  }
 }