logistics.sscc

export function buildSscc(extensionDigit: number, companyPrefix: string, serialReference: number): string

import { buildSscc } from "#fune/logistics.sscc@^1";

import { gs1CheckDigit } from "./validation_gs1_check_digit.ts";  ← from validation.gs1-check-digit ^1.0.0 · built alongside by fune

/**
 * Build an 18-digit SSCC: extension digit, GS1 company prefix, zero-padded
 * serial reference and GS1 mod-10 check digit.
 */
export function buildSscc(extensionDigit: number, companyPrefix: string, serialReference: number): string {
  if (!Number.isInteger(extensionDigit) || extensionDigit < 0 || extensionDigit > 9) {
    throw new RangeError(`extensionDigit must be 0 to 9, received ${extensionDigit}`);
  }
  if (typeof companyPrefix !== "string" || !/^[0-9]{4,12}$/.test(companyPrefix)) {
    throw new RangeError(`companyPrefix must be 4 to 12 digits, received "${companyPrefix}"`);
  }
  if (!Number.isInteger(serialReference)) {
    throw new TypeError(`serialReference must be an integer, received ${serialReference}`);
  }
  if (serialReference < 0) {
    throw new RangeError(`serialReference must not be negative, received ${serialReference}`);
  }
  // Prefix and serial share 16 digits, so a longer prefix leaves less room.
  // Too large is an error: truncating would reuse another unit's number.
  const room = 16 - companyPrefix.length;
  const serial = String(serialReference);
  if (serial.length > room) {
    throw new RangeError(
      `serialReference must fit in ${room} digits after a ${companyPrefix.length}-digit company prefix, received ${serialReference}`,
    );
  }
  const data = String(extensionDigit) + companyPrefix + serial.padStart(room, "0");
  return data + String(gs1CheckDigit(data));
}

Install

fune build

With that line in your source, in a TypeScript project (language typescript in fune.project), fune build resolves it and its 1 dependency, pins them in fune.lock, downloads only the TypeScript package of each, and builds the code above into your project’s .fune/build, one readable file per capability with a header linking back here. Or pin a range in fune.project and build in one step:

fune add logistics.sscc

The manifest, vectors and README with only the TypeScript implementation. Install it without the registry with fune add ./logistics.sscc-1.1.0-typescript.fune, or fetch it from a terminal with fune pull logistics.sscc@1.1.0:typescript.

The whole function, every language, is one file too: logistics.sscc-1.1.0.fune, 10,910 bytes, sha256 aea2a0319e89e237e8778fea97ac8cd01600de11bd63409a4546fd35791a5e55. It installs into a project of any language.

// fune: before logistics.sscc

// fune: after logistics.sscc

// fune: replace validation.gs1-check-digit in logistics.sscc

// fune: step logistics.sscc after <n|label>

More from the author

So a 7-digit prefix leaves 9 digits of serial reference and a 10-digit prefix leaves 6. A serial reference too large for the room left is an error rather than being truncated, because a truncated serial silently re-uses another pallet's number.

## Check digit

The standard GS1 mod-10 over the 17 data digits, from `validation.gs1-check-digit` since 1.1.0 (1.0.0 repeated the arithmetic here, because `validation.gtin` only accepted GTIN lengths). The answers are the same. GS1's own example, `(00) 1 0614141 123456789 7`, is a vector, and so is the SSCC from GS1's check digit worked example, `376104250021234569`.

## What it does not do

- It returns the bare 18 digits. The label's human-readable line shows them after the application identifier as `(00) 106141411234567897`; the barcode (GS1-128) encodes `00` followed by the 18 digits. - It does not allocate serial references. GS1 asks that an SSCC is not re-used for at least a year after the unit was shipped; keeping the counter is the caller's job. - It cannot tell whether a prefix was really allocated to you.

## Source

GS1 General Specifications, the SSCC (logistic units) and check digit calculation sections, https://www.gs1.org/standards/barcodes-epcrfid-id-keys/gs1-general-specifications ; GS1 UK, "How do I create SSCCs and logistics labels?", https://www.gs1uk.org/knowledge-hub/barcodes/how-do-i-create-ssccs-and-logistics-labels

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