fix(no-conditional-statements): allow continue and break statements with labels to be considered "returning" (#846)

Handle labeled break statements and continue statements in switch cases in the no-conditional-statements rule.

Author: RebeccaStevens

src/rules/no-conditional-statements.ts

@@ -17,6 +17,7 @@ import {
   isContinueStatement,
   isExpressionStatement,
   isIfStatement,
+  isLabeledStatement,
   isReturnStatement,
   isSwitchStatement,
   isThrowStatement,
@@ -195,18 +196,6 @@ function getIfBranchViolations(
   return violations.flatMap(incompleteBranchViolation);
 }
 
-/**
- * Is the given statement, when inside a switch statement, a returning branch?
- */
-function isSwitchReturningBranch(statement: TSESTree.Statement) {
-  return (
-    // Another instance of this rule will check nested switch statements.
-    isSwitchStatement(statement) ||
-    isReturnStatement(statement) ||
-    isThrowStatement(statement)
-  );
-}
-
 /**
  * Get all of the violations in the given switch statement assuming switch
  * statements are allowed.
@@ -217,6 +206,8 @@ function getSwitchViolations(
 ): RuleResult<keyof typeof errorMessages, Options>["descriptors"] {
   const isNeverExpressions = getIsNeverExpressions(context);
 
+  const label = isLabeledStatement(node.parent) ? node.parent.label.name : null;
+
   const violations = node.cases.filter((branch) => {
     if (branch.consequent.length === 0) {
       return false;
@@ -241,6 +232,22 @@ function getSwitchViolations(
   });
 
   return violations.flatMap(incompleteBranchViolation);
+
+  /**
+   * Is the given statement, when inside a switch statement, a returning branch?
+   */
+  function isSwitchReturningBranch(statement: TSESTree.Statement) {
+    return (
+      // Another instance of this rule will check nested switch statements.
+      isSwitchStatement(statement) ||
+      isReturnStatement(statement) ||
+      isThrowStatement(statement) ||
+      (isBreakStatement(statement) &&
+        statement.label !== null &&
+        statement.label.name !== label) ||
+      isContinueStatement(statement)
+    );
+  }
 }
 
 /**

src/utils/type-guards.ts

@@ -157,6 +157,12 @@ export function isIfStatement(
   return node.type === AST_NODE_TYPES.IfStatement;
 }
 
+export function isLabeledStatement(
+  node: TSESTree.Node,
+): node is TSESTree.LabeledStatement {
+  return node.type === AST_NODE_TYPES.LabeledStatement;
+}
+
 export function isMemberExpression(
   node: TSESTree.Node,
 ): node is TSESTree.MemberExpression {