How to break promise chain nested into another promise chain - node.js

Question

I am unable to figure out how to break a nested promise chain into a main promise chain. Here is my code :
//Main Promise chain
let promiseMain = Promise.resolve(1)
.then(result => functionA())
.then(result => nestedChain()).catch((error) => {
console.log(error);
})
.then(result => functionC())
//chain error handler
function chainError(err) {
return Promise.reject(err)
};
function nestedChain()
{
stepOne()
.then(stepTwo, chainError)
.then(stepThreee, chainError)
.catch((error) =>
{
console.log(error);
return undefined;
});
}
function stepOne()
{
return chainError("error attempt : 1.00");
}
Once I go into the nestedChain where I throw an error in stepOne() I am able to break this nestedChain. Awesome!
The problem: It also breaks the main promise chain. So.. when it goes into nestedChain() and the error is thrown from stepOne(), functionC from the main promise chain will never be executed because the rejected promise from the nestedChain also break this chain.

Answer 1

You will have to attach with promises chain, do something like this
function nestedChain()
{
stepOne()
.then(stepTwo, chainError)
.then(stepThreee, chainError)
.catch ((error) => {
console.log(error);
return undefined;
})
}

Answer 2

Promise are implemented to wait for something which take more time. You just need to implement promise correctly.
For example if we have 3 function returning promise and one nested function also returning promise, this is how it's implemented:
functionA()
.then( result => {
return functionB();
})
.then( result => {
return nestedFunct();
})
.then( result => {
return functionC();
})
.then( result => {
console.log(result);
})
.catch( error => {
console.log(`Error in one of the above function`);
});
All the function are of format similar too
function functionA() {
return new Promise( (resilve, reject) => {
resolve('something');
// or
reject('Error');
});
}
Nested function can be like this
function nestedFunc() {
return functionD() // Return promise
.then( result => {
return functionE(); // return promise
})
.then( result => {
return functionF(); // return promise or value
});
}
Main promise chain is not affected by what individual function do as long as they keep returning promise. All individual function can have a local promise chain. Even if an error occurred in nested chain will be catched by catch() in main promise chain.

Answer 3

If i understood you correct, you need to catch error after nested chain promise
Promise.resolve().then(()=> {
console.log('A');
}).then(() => {
return Promise.resolve().then(() => {
console.log('step 1');
}).then(() => {
console.log('step 2');
throw new Error('Step 2 error');
});
}).catch((err) => {
console.log(err);
}).then(() => {
console.log('C');
});