finallyStatementSafety

Reports control flow statements in finally blocks that can override control flow in try/catch blocks.

✅ This rule is included in the ts logical and logicalStrict presets.

Control flow statements such as return, throw, break, and continue in finally blocks can cause unexpected behavior. When these statements appear in a finally block, they override any control flow statements in the corresponding try or catch blocks. The finally block always executes, and its control flow statements take precedence, which can lead to bugs that are difficult to diagnose.

function 
function processData(): unknown
processData() {
  try {
    return 
const fetchData: () => unknown
fetchData();
  } finally {
    return null;
  }
}

function 
function handleError(): void
handleError() {
  try {
    throw new 
var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)
Error("Original error");
  } catch (
function (local var) error: unknown
error) {
    throw 
function (local var) error: unknown
error;
  } finally {
    throw new 
var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)
Error("Override error");
  }
}

for (let 
let i: number
i = 0; 
let i: number
i < 
const items: unknown[]
items.
Array<unknown>.length: number
Gets or sets the length of the array. This is a number one higher than the highest index in the array.
length; 
let i: number
i++) {
  try {
    
const processItem: (item: unknown) => void
processItem(
const items: unknown[]
items[
let i: number
i]);
  } finally {
    break;
  }
}

function 
function processData(): unknown
processData() {
  try {
    return 
const fetchData: () => unknown
fetchData();
  } finally {
    
const cleanup: () => void
cleanup();
  }
}

function 
function handleError(): void
handleError() {
  try {
    throw new 
var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)
Error("Original error");
  } catch (
function (local var) error: unknown
error) {
    
var console: Console
The console module provides a simple debugging console that is similar to the
JavaScript console mechanism provided by web browsers.
The module exports two specific components:

A Console class with methods such as console.log(), console.error() and console.warn() that can be used to write to any Node.js stream.
A global console instance configured to write to process.stdout and
process.stderr. The global console can be used without importing the node:console module.

Warning: The global console object's methods are neither consistently
synchronous like the browser APIs they resemble, nor are they consistently
asynchronous like all other Node.js streams. See the note on process I/O for
more information.
Example using the global console:
console.log('hello world');
// Prints: hello world, to stdout
console.log('hello %s', 'world');
// Prints: hello world, to stdout
console.error(new Error('Whoops, something bad happened'));
// Prints error message and stack trace to stderr:
//   Error: Whoops, something bad happened
//     at [eval]:5:15
//     at Script.runInThisContext (node:vm:132:18)
//     at Object.runInThisContext (node:vm:309:38)
//     at node:internal/process/execution:77:19
//     at [eval]-wrapper:6:22
//     at evalScript (node:internal/process/execution:76:60)
//     at node:internal/main/eval_string:23:3

const name = 'Will Robinson';
console.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to stderr
Example using the Console class:
const out = getStreamSomehow();
const err = getStreamSomehow();
const myConsole = new console.Console(out, err);

myConsole.log('hello world');
// Prints: hello world, to out
myConsole.log('hello %s', 'world');
// Prints: hello world, to out
myConsole.error(new Error('Whoops, something bad happened'));
// Prints: [Error: Whoops, something bad happened], to err

const name = 'Will Robinson';
myConsole.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to err
@see ― source
console.
Console.error(message?: any, ...optionalParams: any[]): void (+1 overload)
Prints to stderr with newline. Multiple arguments can be passed, with the
first used as the primary message and all additional used as substitution
values similar to printf(3)
(the arguments are all passed to util.format()).
const code = 5;
console.error('error #%d', code);
// Prints: error #5, to stderr
console.error('error', code);
// Prints: error 5, to stderr
If formatting elements (e.g. %d) are not found in the first string then
util.inspect() is called on each argument and the
resulting string values are concatenated. See util.format()
for more information.
@since ― v0.1.100
error(
function (local var) error: unknown
error);
    throw 
function (local var) error: unknown
error;
  } finally {
    
const cleanup: () => void
cleanup();
  }
}

for (let 
let i: number
i = 0; 
let i: number
i < 
const items: unknown[]
items.
Array<unknown>.length: number
Gets or sets the length of the array. This is a number one higher than the highest index in the array.
length; 
let i: number
i++) {
  try {
    
const processItem: (item: unknown) => void
processItem(
const items: unknown[]
items[
let i: number
i]);
    break;
  } finally {
    
const cleanup: () => void
cleanup();
  }
}

Options

This rule is not configurable.

When Not To Use It

If you are very confident in your handling of exception handling in your code and specifically want to use the confusing quirks of finally control flow statements, this rule might not be for you.

Equivalents in Other Linters

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finallyStatementSafety

Examples

Options

When Not To Use It

Further Reading

Equivalents in Other Linters