rspec/rules/S4822/javascript/rule.adoc

An exception (including ``++reject++``) thrown by a promise will not be caught by a nesting ``++try++`` block, due to the asynchronous nature of execution. Instead, use ``++catch++`` method of ``++Promise++`` or wrap it inside ``++await++`` expression.


This rule reports ``++try-catch++`` statements containing nothing else but call(s) to a function returning a ``++Promise++`` (thus it's less likely that ``++catch++`` is intended to catch something else than ``++Promise++`` rejection).


== Noncompliant Code Example

[source,javascript]
----
function runPromise() {
  return Promise.reject("rejection reason");
}

function foo() {
  try { // Noncompliant, the catch clause of the 'try' will not be executed for the code inside promise
    runPromise();
  } catch (e) {
    console.log("Failed to run promise", e);
  }
}
----


== Compliant Solution

[source,javascript]
----
function foo() {
  runPromise().catch(e => console.log("Failed to run promise", e));
}

// or
async function foo() {
  try {
    await runPromise();
  } catch (e) {
    console.log("Failed to run promise", e);
  }
}
----

ifdef::env-github,rspecator-view[]

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== Implementation Specification
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include::message.adoc[]

include::highlighting.adoc[]

endif::env-github,rspecator-view[]