How to use the antlr4ts/atn.TransitionType.PREDICATE function in antlr4ts

set.path = ruleStack.slice();
            followSets.push(set);
            return;
        }

        for (let transition of s.getTransitions()) {
            if (transition.serializationType == TransitionType.RULE) {
                let ruleTransition: RuleTransition = transition as RuleTransition;
                if (ruleStack.indexOf(ruleTransition.target.ruleIndex) != -1)
                    continue;

                ruleStack.push(ruleTransition.target.ruleIndex);
                this.collectFollowSets(transition.target, stopState, followSets, seen, ruleStack);
                ruleStack.pop();

            } else if (transition.serializationType == TransitionType.PREDICATE) {
                if (this.checkPredicate(transition as PredicateTransition))
                    this.collectFollowSets(transition.target, stopState, followSets, seen, ruleStack);
            } else if (transition.isEpsilon) {
                this.collectFollowSets(transition.target, stopState, followSets, seen, ruleStack);
            } else if (transition.serializationType == TransitionType.WILDCARD) {
                let set = new FollowSetWithPath();
                set.intervals = IntervalSet.of(Token.MIN_USER_TOKEN_TYPE, this.atn.maxTokenType);
                set.path = ruleStack.slice();
                followSets.push(set);
            } else {
                let label = transition.label;
                if (label && label.size > 0) {
                    if (transition.serializationType == TransitionType.NOT_SET) {
                        label = label.complement(IntervalSet.of(Token.MIN_USER_TOKEN_TYPE, this.atn.maxTokenType));
                    }
                    let set = new FollowSetWithPath();