octobercms/october · error · Error

Broken JSON array near ${result}

Error message

Broken JSON array near ${result}

What it means

Array-branch counterpart in JsonParser.parseString (October CMS AJAX framework). The scanner walks a [..] literal inserting null for empty slots on commas, and returns only on the final ']'; if input ends first, it throws with the partially built strict-JSON array in the message.

Source

Thrown at modules/system/assets/js/framework.js:2182

            var body = this.getBody(str, i);
            i = i + body.originLength - 1;
            result += this.parseString(body.body);
            type = "afterBody";
          } else if (type === "afterBody") {
            if (str[i] === ",") {
              result += ",";
              type = "needBody";
              while (str[i + 1] === "," || this.isBlankChar(str[i + 1])) {
                if (str[i + 1] === ",") result += "null,";
                i++;
              }
            } else if (str[i] === "]" && i === str.length - 1) {
              result += "]";
              return result;
            }
          }
        }
        throw new Error("Broken JSON array near " + result);
      }
    }
    parseKey(str, pos, quote) {
      var key = "";
      for (var i = pos; i < str.length; i++) {
        if (quote && quote === str[i]) {
          return key;
        } else if (!quote && (str[i] === " " || str[i] === ":")) {
          return key;
        }
        key += str[i];
        if (str[i] === "\\" && i + 1 < str.length) {
          key += str[i + 1];
          i++;
        }
      }
      throw new Error("Broken JSON syntax near " + key);
    }

View on GitHub (pinned to b608633a7e)

Solutions

1. Add the missing ']' (count brackets: every [ needs its ])
2. Repair unterminated inner strings/objects first - they can swallow the closing bracket
3. Build arrays in code with JSON.stringify rather than string assembly

Example fix

<!-- before -->
<div data-request-data="[10, 20">...</div>

<!-- after -->
<div data-request-data="[10, 20]">...</div>

function arrayLiteralCloses(s) {
  const t = s.trim();
  if (t[0] !== '[') return true;
  return (t.match(/\[/g) || []).length === (t.match(/\]/g) || []).length;
}

try { const d = oc.parseJSON(raw); } catch (e) { if (/Broken JSON array near/.test(e.message)) console.error('Unterminated [ - missing closing bracket:', e.message); }

When it happens

Trigger: oc.parseJSON("[1, 2") or data-request-data="[10, 20" - the closing ] never arrives; also values like [1, 'a' where the last element is left unterminated, swallowing the rest.

Common situations: Truncated array attributes from length-limited template output; hand-editing lists and deleting the closer; nested cases ([1, [2, 3]) where an inner ] is missing so the outer never closes.

Related errors

• Broken JSON object near ${result}
• Broken JSON boolean body near ${str}
• Broken JSON number body near ${body}
• Error parsing the ${name} attribute value. ${e}
• Error parsing the ${name} attribute value. ${e}

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/04439a7e87c1a2e1. Report an issue: GitHub.