Thanks for the PR,@anikethsaha!

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could you please gate this functionality behind an option, as per my comment:#647 (comment)

I want end-users to opt-in to this functionality so that they're consciously making the decision for a little unsafety from the rule.

ok cool, also it should only check for async iife right ? not just iife ?

it should check both - it should just be looking for an IIFE that returns a promise.

it should check both - it should just be looking for an IIFE that returns a promise.

make sense , ok creating an options nameignoreIife

@bradzacher I think we need to change the selector for AST as well, cause

currently inExpressionStatement

I have this check

if(options.ignoreIife&&isAsyncIife(node)){return;}

And, here is the definition ofisAsyncIife

functionisAsyncIife(node:TSESTree.ExpressionStatement):Boolean{if(node?.expression.type===AST_NODE_TYPES.AwaitExpression){returntrue}if(node?.expression.type===AST_NODE_TYPES.CallExpression){if(possibleIifeCalleType.has(node?.expression?.callee.type)){if(node?.expression?.callee?.hasAsync){returntrue;}returnnode?.expression?.callee?.body?.body.some(hasPromise);}}returnfalse;}

And here ishasPromise

functionhasPromise(node:TSESTree.ExpressionStatement|TSESTree.ReturnStatement):Boolean{// has promise statementif(node?.expression.type==="NewExpression"&&node?.expression?.callee.name==="Promise"){returntrue;}if(// returning promisenode.type===AST_NODE_TYPES.ReturnStatement&&node?.argument.type===AST_NODE_TYPES.NewExpression&&node?.argument?.callee.name==="Promise"){returntrue;}returnfalse}

It looks like when I give input like this

//  options : [{ ignoreIife : true }](asyncfunction(){// error cause of thisawaitres(1);})();

still the there is a floating error.

I did try changing the selectors

["ExpressionStatement > :not(ExpressionStatement )"](node){check(node)},"ExpressionStatement > ExpressionStatement "(node){if(node?.expression.type===AST_NODE_TYPES.AwaitExpression){returntrue}check(node)}

Still no luck

the code you've got currently in the PR doesn't look too far off.

I'd expect something along the lines of:

ExpressionStatement(node):void{if(options.ignoreIIFE&&isIIFE(node)){return;}// old code}functionisIIFE(node:TSESTree.ExpressionStatement):boolean{constexpr=node.expression;if(expr.type!==AST_NODE_TYPES.CallExpression){returnfalse;}return(expr.callee.type===AST_NODE_TYPES.ArrowFunctionExpression||expr.callee.type===AST_NODE_TYPES.FunctionExpression);}

To clarify what this option should do:

These cases should error withignoreIIFE: false (the default)
They shouldnot error withignoreIIFE: true

(functionfoo(){returnPromise.resolve()})();(asyncfunctionfoo(){returnPromise.resolve()})();(async()=>{returnPromise.resolve()})();

However, setting the option to true should not ignore the contents of an IIFE. I.e. this should still error withignoreIIFE: true

(async()=>{Promise.resolve();// error - floating promise})();// no other lint error

@bradzacher should I add custom type forisAsyncIife method as I addedTSESTree.ExpressionStatement | TSESTree.ArrowFunctionExpression | TSESTree.TSTypeAnnotation type tonode but still typecheck is failing.
also, i triednode?.expression.typeAnnotation.typeand still it failed

Codecov Report

Merging#1799 intomaster willincrease coverage by0.00%.
The diff coverage is100.00%.

@@           Coverage Diff           @@##           master    #1799   +/-   ##=======================================  Coverage   94.37%   94.37%           =======================================  Files         164      164             Lines        7572     7579    +7       Branches     2175     2178    +3     =======================================+ Hits         7146     7153    +7  Misses        183      183             Partials      243      243

make sure you run prettier over your code

https://github.com/typescript-eslint/typescript-eslint/blob/master/CONTRIBUTING.md#validating-your-changes

same issue here as well