An order note fits a character-count limit but exceeds a downstream byte budget. Cutting its encoded bytes at an arbitrary position can split a multibyte sequence. For a Shopify 3PL review screen, build an explicitly shortened preview while preserving the complete original instruction.
The TextEncoder encode() method returns UTF-8 bytes. The example below counts those bytes one Unicode code point at a time. It rejects ill-formed input using isWellFormed(), which detects lone surrogates.
Return the shortened state with the preview
This is a local display helper. It must not replace the original packing instruction or silently shorten an outbound message. It returns the full byte count and a flag so the interface can offer the complete text separately.
'use strict'; const assert = require('node:assert/strict'); const encoder = new TextEncoder(); function notePreview(text, maxBytes) { if (typeof text !== 'string' || !text.isWellFormed()) { throw new Error('Well-formed text required'); } if (!Number.isSafeInteger(maxBytes) || maxBytes < 0) { throw new Error('Nonnegative safe byte budget required'); } let preview = '', used = 0; for (const point of text) { const size = encoder.encode(point).length; if (used + size > maxBytes) break; preview += point; used += size; } return { preview, shortened: preview !== text, fullBytes: encoder.encode(text).length }; } const text = 'A📦中Z'; const expected = ['', 'A', 'A', 'A', 'A', 'A📦', 'A📦', 'A📦', 'A📦中', text]; for (let budget = 0; budget <= 9; budget++) { const result = notePreview(text, budget); const bytes = encoder.encode(result.preview); assert.equal(result.preview, expected[budget]); assert.ok(bytes.length <= budget); assert.equal(new TextDecoder('utf-8', { fatal: true }).decode(bytes), result.preview); assert.equal(result.shortened, budget < 9); assert.equal(result.fullBytes, 9); } assert.equal(text, 'A📦中Z'); assert.deepEqual(notePreview('', 0), { preview: '', shortened: false, fullBytes: 0 }); for (const budget of [-1, 1.5, NaN, '4']) { assert.throws(() => notePreview(text, budget)); } assert.throws(() => notePreview('\uD800', 4)); console.log('UTF-8 preview boundary checks passed'); Save as note-preview.cjs and run node note-preview.cjs with Node.js 24. The checks exercise every byte boundary of ASCII, an emoji and a Chinese code point, plus invalid budgets and malformed input. No request is sent.
Preserve the operational text
A drop shipping review may show a supplier instruction, while a shopify fulfillment screen may show a seller-approved packing note. Keep the original value available and mark a shortened display clearly. If a real receiving API rejects an overlong field, resolve that error through its documented contract instead of sending this preview.
For China fulfillment, agree whether a limit counts bytes, code points or another unit. A China 3PL interface should also specify the encoding. This helper does not preserve whole grapheme clusters: combining marks and joined emoji can span multiple code points. It is unsuitable when those display boundaries must remain intact.
In a hypothetical brief named “International Fulfillment for Folligen,” document the actual field contract before using a display helper. I work with YX Fulfillment; its Shopify handover guide provides related business context. This executable example is not a deployed connector and does not establish a tested store integration.
Warehouse workstations and equipment.
