gchq/CyberChef · error · TypeError

flowControl operations like ${ing.opName} are not currently

Error message

flowControl operations like ${ing.opName} are not currently allowed in recipes for chef.bake in the Node API

What it means

Thrown by NodeRecipe._validateIngredient when the ingredient is a function (an operation class) but its flowControl flag is set. The Node API deliberately excludes flow-control operations (Fork, Magic, etc.) from chef.bake recipes because they manipulate the recipe graph itself, which the Node execution model does not support.

Source

Thrown at src/node/NodeRecipe.mjs:48

     *  operation and its arguments
     * @throws {TypeError} If it cannot find the operation in chef's list of operations.
     */
    _validateIngredient(ing) {
        // CASE operation name given. Find operation and validate
        if (typeof ing === "string") {
            const op = operations.find((op) => {
                return sanitise(op.opName) === sanitise(ing);
            });
            if (op) {
                // Need to validate against case 2
                return this._validateIngredient(op);
            } else {
                throw new TypeError(`Couldn't find an operation with name '${ing}'.`);
            }
        // CASE operation given. Check its a chef operation and check its not flowcontrol
        } else if (typeof ing === "function") {
            if (ing.flowControl) {
                throw new TypeError(`flowControl operations like ${ing.opName} are not currently allowed in recipes for chef.bake in the Node API`);
            }

            if (operations.includes(ing)) {
                return ing;
            } else {
                throw new TypeError("Inputted function not a Chef operation.");
            }
        // CASE: op, maybe with configuration
        } else if (ing.op) {
            const sanitisedOp = this._validateIngredient(ing.op);
            if (ing.args) {
                return {op: sanitisedOp, args: ing.args};
            }
            return sanitisedOp;
        } else {
            throw new TypeError("Recipe can only contain function names or functions");
        }
    }

View on GitHub (pinned to 4290ea7539)

Solutions

  1. Remove the flowControl operation from the Node recipe.
  2. Reimplement its effect with a script or a different sequence of supported operations.
  3. For Magic-style detection, run candidate recipes yourself instead of using the Magic op.

Example fix

// before
chef.bake(input, [Fork, "From Hex"]); // Fork is flowControl
// after
chef.bake(input, ["From Hex"]);
Defensive patterns

Strategy: validation

Validate before calling

function assertNoFlowControl(recipe) {
  for (const ing of recipe) if (typeof ing === "function" && ing.flowControl) throw new Error(`${ing.opName} is flowControl and unsupported in Node`);
}

Type guard

const isFlowControl = (ing) => typeof ing === "function" && ing.flowControl === true;

Try / catch

try { chef.bake(input, recipe); } catch (e) { if (e instanceof TypeError && /flowControl operations/.test(e.message)) { /* remove op */ } else throw e; }

Prevention

When it happens

Trigger: A recipe includes a flowControl operation passed as a function reference (e.g. chef.operations.Fork or the imported operation class). The check is ing.flowControl === true at validation time.

Common situations: Porting a browser recipe that uses Fork/Magic/Register/Label to the Node API; importing operations directly from src and adding them to a recipe array.

Related errors

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/d3e8d33c4ef90cea. Report an issue: GitHub.