Function wrapWithPredicates

packages/forms/signals/src/schema/logic.ts:221–247

* Wraps a logic function such that it returns the special `IGNORED` sentinel value if any of the * given predicates evaluates to false. * * @param predicates A list of bound predicates to apply to the logic function * @param logicFn The logic function to wrap * @returns A wrapped version of the

(
  predicates: ReadonlyArray<BoundPredicate>,
  logicFn: LogicFn<TValue, TReturn>,
)

 * @returns A wrapped version of the logic function that may return `IGNORED`.
 */
function wrapWithPredicates<TValue, TReturn>(
  predicates: ReadonlyArray<BoundPredicate>,
  logicFn: LogicFn<TValue, TReturn>,
): LogicFn<TValue, TReturn | typeof IGNORED> {
  if (predicates.length === 0) {
    return logicFn;
  }
  return (arg: FieldContext<any>): TReturn | typeof IGNORED => {
    for (const predicate of predicates) {
      let predicateField = arg.stateOf(predicate.path) as FieldNode;
      // Check the depth of the current field vs the depth this predicate is supposed to be
      // evaluated at. If necessary, walk up the field tree to grab the correct context field.
      // We can check the pathKeys as an untracked read since we know the structure of our fields
      // doesn't change.
      const depthDiff = untracked(predicateField.structure.pathKeys).length - predicate.depth;
      for (let i = 0; i < depthDiff; i++) {
        predicateField = predicateField.structure.parent!;
      }
      // If any of the predicates don't match, don't actually run the logic function, just return
      // the default value.
      if (!predicate.fn(predicateField.context)) {
        return IGNORED;
      }
    }
    return logicFn(arg);
  };
}

/**
 * Container for all the different types of logic that can be applied to a field