gchq/CyberChef · error · OperationError

${e}

Error message

${e}

What it means

The Template operation compiles a Handlebars template string and renders it against the JSON input. Any error raised by Handlebars.compile() or by invoking the compiled template — syntax errors, unknown helpers, type errors during rendering — is caught and rethrown as an OperationError whose message is the original error.

Solutions

1. Validate the template syntax in an external Handlebars playground before pasting it in.
2. Ensure every block helper {{#x}} has a matching {{/x}}.
3. Remove references to helpers that are not part of Handlebars core.
4. Feed valid JSON input that matches the fields the template references.

Example fix

// before: template = "{{#each items}}{{name}}{{/loop}}"  (mismatched block name)
// after:  template = "{{#each items}}{{name}}{{/each}}"

let compiled;
try { compiled = Handlebars.compile(templateStr); }
catch (e) { throw new Error(`Template syntax invalid: ${e.message}`); }
return compiled(jsonInput);

function isCompilableTemplate(tpl) {
  try { Handlebars.precompile(tpl); return true; } catch { return false; }
}

try { chef.Template(jsonInput, [templateStr]); }
catch (e) { if (/Parse error|Expecting/.test(e.message)) { /* fix template syntax */ } else throw e; }

When it happens

Trigger: A malformed Handlebars template (unbalanced braces, unclosed block like {{#each}} without {{/each}}, or an unterminated expression); referencing a helper that is not registered; or rendering a template whose partial/helper expects a type the JSON input does not provide.

Common situations: Authoring a template with a typo in block syntax; using a custom helper that Handlebars does not ship; passing non-object JSON that the template indexes into.

Related errors

• Could not encode JSON to MessagePack
• ${err.toString()}
• Invalid input JSON
• Invalid input JSON
• Invalid jq expression

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/e34288024dfbcccb. Report an issue: GitHub.

Appendix: source

Thrown at src/core/operations/Template.mjs:48

                name: "Template definition (.handlebars)",
                type: "text",
                value: ""
            }
        ];
    }

    /**
     * @param {JSON} input
     * @param {Object[]} args
     * @returns {string}
     */
    run(input, args) {
        const [templateStr] = args;
        try {
            const template = Handlebars.compile(templateStr);
            return template(input);
        } catch (e) {
            throw new OperationError(e);
        }
    }
}

export default Template;

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