Nodejs - class with async await does nothing - node.js

Question

I am fairly new to Node.JS, but have some experience in other languages. I am trying to achieve the following:
I want to perform a task and if it fails perform another task.
I have two files: one is the main function, the other contains the class.
First the main function (main.js):
(async function main() {
let { MyClass } = require("./my_class.js");
const mc = new MyClass();
await mc.do_stuff();
console.log(mc.message);
})();
The other is the class (my_class.js)
class MyClass {
constructor() {
this.message='hello';
}
do_stuff=async function() {
return new Promise((resolve,reject) => async function (){
let [res,rej]=await do_first('fail');
if(rej) {
console.log('do_first() failed.');
[res,rej]=await do_second('succeed');
if(rej) {
console.log('do_second() failed.');
reject('failed');
} else {
console.log('do_second() succeeded.');
resolve('success');
}
} else {
console.log('do_first() succeeded, no call to do_second().');
resolve('success');
}
});
}
do_first=async function(param) {
return new Promise((resolve,reject) => {
if(param==='fail') {
console.log('rejecting do_first()');
reject('failure');
} else {
console.log('resolving do_first()');
resole('success');
}
});
}
do_second=async function(param) {
return new Promise((resolve,reject) => {
if(param==='fail') {
console.log('rejecting do_second()');
reject('failure');
} else {
console.log('resolving do_second()');
resole('success');
}
});
}
}
exports.MyClass = MyClass
If I try to run it with node ./main.js nothing happens. If I run mc.do_stuff() without the await, I do get the hello... Which boats am I missing?
For that matter: I am running NodeJS v18.12.0

Answer 1

A few things need to be changed here to make it work:
When using await, only the Promise.resolve comes back to regular code execution. Promise.reject always raises an Exception.
Typo resole
changed code to consistently use arrow syntax. This requires referencing functions as instance members -> this.do_first. I suppose this was your intention. The syntax before did not execute the function as part of the object, but in global scope.
Here's your code in a working state
class MyClass {
constructor() {
this.message = "hello";
}
do_stuff = async () => {
return new Promise(async (resolve, reject) => {
try {
await this.do_first("fail");
console.log("do_first() succeeded, no call to do_second().");
resolve("success");
} catch (err) {
console.log("do_first() failed.");
try {
await this.do_second("succeed");
console.log("do_second() succeeded.");
resolve("success");
} catch (err) {
console.log("do_second() failed.");
reject("failed");
}
}
});
};
do_first = async (param) => {
return new Promise(async (resolve, reject) => {
if (param === "fail") {
console.log("rejecting do_first()");
reject("failure");
} else {
console.log("resolving do_first()");
resolve("success");
}
});
};
do_second = async (param) => {
return new Promise((resolve, reject) => {
if (param === "fail") {
console.log("rejecting do_second()");
reject("failure");
} else {
console.log("resolving do_second()");
resolve("success");
}
});
};
}
exports.MyClass = MyClass;
PS C:\Users\patrick\Documents\GitHub\stackoverflow-74714360> node ./main.js
rejecting do_first()
do_first() failed.
resolving do_second()
do_second() succeeded.
hello