octobercms/october · error · Error

Broken JSON ${str[pos] === "{" ? "object" : "array"} body ne

Error message

Broken JSON ${str[pos] === "{" ? "object" : "array"} body near ${body}

What it means

Thrown while JsonParser.getBody bracket-matches an object or array body in October CMS's relaxed JSON. The parser keeps a stack of open brackets and quotes; when it encounters '}' and the innermost open bracket is not '{' (for example a '{' appearing while only '[' is open), the structure cannot be balanced and it throws, echoing the body scanned so far.

Source

Thrown at modules/system/assets/js/framework-bundle.js:2306

            if (stack[stack.length - 1] === '"') {
              stack.pop();
            } else if (stack[stack.length - 1] !== "'") {
              stack.push(str[i]);
            }
          } else if (str[i] === "'") {
            if (stack[stack.length - 1] === "'") {
              stack.pop();
            } else if (stack[stack.length - 1] !== '"') {
              stack.push(str[i]);
            }
          } else if (stack[stack.length - 1] !== '"' && stack[stack.length - 1] !== "'") {
            if (str[i] === "{") {
              stack.push("{");
            } else if (str[i] === "}") {
              if (stack[stack.length - 1] === "{") {
                stack.pop();
              } else {
                throw new Error("Broken JSON " + (str[pos] === "{" ? "object" : "array") + " body near " + body);
              }
            } else if (str[i] === "[") {
              stack.push("[");
            } else if (str[i] === "]") {
              if (stack[stack.length - 1] === "[") {
                stack.pop();
              } else {
                throw new Error("Broken JSON " + (str[pos] === "{" ? "object" : "array") + " body near " + body);
              }
            }
          }
          if (!stack.length) {
            return {
              originLength: i - pos,
              body
            };
          }
        }

View on GitHub (pinned to b608633a7e)

Solutions

  1. Balance the brackets in the attribute value: add the missing ']' (e.g. {items: [1,2]}) and remove the extra '}'
  2. Run the value through a bracket-balance check or oc.parseJSON before wiring it to a request
  3. Author the attribute as strict JSON generated by JSON.stringify/json_encode so tooling can validate it

Example fix

<!-- before -->
<div data-request-data="{items: [1,2}}">...</div>

<!-- after -->
<div data-request-data="{items: [1,2]}">...</div>
Defensive patterns

Strategy: validation

Validate before calling

function bracketsBalanced(s) {
  let depth = 0;
  for (const ch of s) {
    if (ch === '{' || ch === '[') depth++;
    else if (ch === '}' || ch === ']') depth--;
    if (depth < 0) return false; // closer with nothing open
  }
  return depth === 0;
}
const ok = bracketsBalanced(el.getAttribute('data-request-data') || '');

Try / catch

try { oc.request(el, 'onGo'); } catch (e) { if (/Broken JSON (object|array) body/.test(e.message)) { console.error('Unbalanced brackets in data attributes:', e.message); } }

Prevention

When it happens

Trigger: oc.parseJSON("{items: [1,2}}") - the first '}' closes nothing because the top of the stack is '['; likewise data-request-update="{'partial': '#id'}}" with an extra closing brace inside a nested array context.

Common situations: Extra '}' typed at the end of hand-written attribute values; nesting edits (adding an array literal) without updating brackets; regex/string processing of attributes that appends stray braces; minified or hand-compressed markup losing a ']' before a '}'.

Related errors

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/306dda3dbd7a61b7. Report an issue: GitHub.