affaan-m/ECC · error · Error

${label} must be an array.

Error message

${label} must be an array.

What it means

Thrown by uniqueStrings() when the values argument is not an array. uniqueStrings is the shared validator for list-valued memory fields (tags, links, targetHarnesses, etc.) and requires an actual Array instance.

Source

Thrown at scripts/lib/memory-vault-format.js:117

function validateSlug(value, label) {
  const normalized = asNonEmptyString(value, label, 64);
  if (!SLUG_PATTERN.test(normalized)) {
    throw new Error(`${label} must be a lowercase letters/numbers slug.`);
  }
  return normalized;
}

function validateMemoryId(value) {
  const normalized = asNonEmptyString(value, 'memory id', 132);
  if (!MEMORY_ID_PATTERN.test(normalized)) {
    throw new Error('memory id must match mem_<lowercase-id> and cannot contain a path.');
  }
  return normalized;
}

function uniqueStrings(values, { label, limit, validator }) {
  if (!Array.isArray(values)) {
    throw new Error(`${label} must be an array.`);
  }
  if (values.length > limit) {
    throw new Error(`${label} has too many values (maximum ${limit}).`);
  }
  return values.reduce((result, value) => {
    const normalized = validator(value);
    if (result.includes(normalized)) {
      throw new Error(`${label} must not contain duplicate values.`);
    }
    return [...result, normalized];
  }, []);
}

function validateTimestamp(value, label) {
  const normalized = asNonEmptyString(value, label, 64);
  const parsed = new Date(normalized);
  if (
    !ISO_TIMESTAMP_PATTERN.test(normalized)

View on GitHub (pinned to 01e15490f0)

Solutions

1. Wrap the value in an array before passing it (Array.isArray check, or Array.from / [].concat).
2. Fix the upstream producer so the field is always a list.
3. If the field is optional, pass an empty array rather than null.

Example fix

// before
uniqueStrings('tag-a,tag-b', { label: 'tags', limit: 32, validator: v => v });
// after
uniqueStrings(['tag-a', 'tag-b'], { label: 'tags', limit: 32, validator: v => v });

function asStringArray(value) {
  return Array.isArray(value) ? value : (value == null ? [] : [value]);
}
// before calling uniqueStrings:
const tags = asStringArray(raw.tags);

function isStringArray(value) {
  return Array.isArray(value) && value.every(v => typeof v === 'string');
}

try {
  result = uniqueStrings(values, opts);
} catch (e) {
  if (/must be an array/.test(e.message)) result = uniqueStrings(values == null ? [] : [values], opts);
  else throw e;
}

When it happens

Trigger: Passing a comma-separated string instead of an array, an object, undefined, or null where the schema expects a list.

Common situations: Deserializing frontmatter that has a scalar where a list was expected; a generator that conditionally produces a single value instead of a list.

Related errors

• ${label} must be a non-empty string.
• ${label} must be a lowercase letters/numbers slug.
• memory id must match mem_<lowercase-id> and cannot contain a
• ${label} has too many values (maximum ${limit}).
• ${label} must not contain duplicate values.

AI-assisted analysis of affaan-m/ECC@01e15490f0 (2026-08-13). Data as JSON: /api/errors/09d7bbcdd9254660. Report an issue: GitHub.