inhibitIf

Returns a step that yields the same values as the passed in step, but downstream work is inhibited whenever the condition step yields true.

Not a security boundary

inhibitIf enables Grafast to optimize away unnecessary downstream work; it does not guarantee that the work will not execute. Do not use it for authorization or to prevent security-sensitive operations. Enforce those requirements inside the protected operation or data source.

Unlike inhibitOnNull, inhibitIf is an explicit step in the plan, so it will typically appear in plan diagrams as its own node.

Declarative flow

The inhibition only affects steps that depend on the wrapper step (and those that depend on those, and so on); steps depending on the original (unwrapped) step are not otherwise impacted.

Example

const $myList = fieldArgs.getRaw("myList");
const $isEmpty = lambda($myList, (list) => list.length === 0, true);
const $guardedList = inhibitIf($myList, $isEmpty);
const $result = doSomethingWith($guardedList);
return trap($result, TRAP_INHIBITED, {
  valueForInhibited: "EMPTY_LIST",
});

In the example above, when $isEmpty yields true, the dependent work is inhibited and Grafast can omit the affected entries from downstream execution. When the condition yields false, the wrapped step behaves as a pass-through.

Plan diagrams

inhibitIf is a regular step, so plan diagrams will generally show it explicitly: