Await on an async lambda function gjs - gjs

Question

I'm trying to get make the async calls bellow (they are async because of a external API, not my design) to run sequentially, now I managed to have foo be awaited by it's calling function but I'm having trouble awaiting for foo2 because I get the following error on the async line
JS ERROR: SyntaxError: missing ) after argument list
What am I missing?
ps: Also is there a better way to "return" a value from the callback than setting a global variable and accessing it from outside?
foo(nick) {
return new Promise((resolve, reject) async () => {
async_foo(par, [],
(c, res) => {
let par2;
try {
par2 = c.somefun(res);
} catch (e) {
logError(e, `Some error`);
return;
}
let output = await this.foo2(par2);
resolve(output);
});
});
}
foo2(par2) {
return new Promise((resolve, reject) => {
par2.asyncfun(
null, this.callback.bind(this, par2));
});
}
Thank you in advance

Answer 1

I think you're just trying to do too much in one Promise:
async function(nick) {
let res1 = await new Promise((resolve, reject) => {
async_foo(par, [], (c, res) => {
try {
resolve(async_foo_finish(res));
} catch (e) {
reject(e);
}
});
});
return new Promise((resolve, reject) => {
res1.asyncfunc(null, (obj, res) => {
try {
resolve(obj.asyncfun_finish(res));
} catch (e) {
reject(e);
}
});
});
}
foo('something').then(output => {
log('output');
}).catch(e => {
logError(e);
});
It's hard to give good advice, since you're not showing real functions.
One of the main purposes of Promises/async-await is to avoid complicated callback nesting. You should generally break your chain of functions into separate Promises, then await them one after the other.