Terminado sprint 2A

lib/conditional.ts

@@ -0,0 +1,53 @@
+import type { ConditionalRule, FormAnswers, Question } from './types'
+
+/** Returns true if the question should be shown given the current answers. */
+export function isQuestionVisible(
+  question: Question,
+  answers: FormAnswers
+): boolean {
+  const rules = question.conditional_rules
+  if (!rules || rules.length === 0) return true
+  // All rules must pass (AND semantics)
+  return rules.every((rule) => evaluateRule(rule, answers))
+}
+
+function evaluateRule(rule: ConditionalRule, answers: FormAnswers): boolean {
+  if (rule.op === 'eq') {
+    return answers[rule.if_question] === rule.value
+  }
+  return false
+}
+
+/**
+ * Returns the codes of questions that will become hidden when `triggerCode`
+ * changes to `newValue`. Used to clear those answers reactively.
+ */
+export function getHiddenCodes(
+  triggerCode: string,
+  newValue: string | string[] | number | null,
+  questions: Question[],
+  currentAnswers: FormAnswers
+): string[] {
+  const projected = { ...currentAnswers, [triggerCode]: newValue }
+  return questions
+    .filter((q) => {
+      if (!q.conditional_rules?.length) return false
+      const dependsOnTrigger = q.conditional_rules.some(
+        (r) => r.if_question === triggerCode
+      )
+      if (!dependsOnTrigger) return false
+      return !isQuestionVisible(q, projected)
+    })
+    .map((q) => q.code)
+}
+
+/** All trigger codes in the survey (questions that have dependents). */
+export function getTriggerCodes(questions: Question[]): Set<string> {
+  const triggers = new Set<string>()
+  for (const q of questions) {
+    for (const rule of q.conditional_rules ?? []) {
+      triggers.add(rule.if_question)
+    }
+  }
+  return triggers
+}