Mixing
WHy am I getting a SyntaxError: Unexpected identifier in forEach with await?
I have an object with a series of named SQL query templates that I'm trying to execute.
The query() method is async, so I should be able to run it with await, but I get an Unexpected identifier error. If I take off the await, then I don't get an error, but I'm stuck with a Promise object...
Object.entries(sqlquerries).forEach(([queryName, queryTpl]) => {
try {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
} catch (err) {
console.error('An error occured running the query : ', err );
}
});
return report;
Why would that be? What can I do to construct my report object and get around this error?
Any help/pointers would be greatly appreciated.
javascript promise async-await
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
add a comment |
I have an object with a series of named SQL query templates that I'm trying to execute.
The query() method is async, so I should be able to run it with await, but I get an Unexpected identifier error. If I take off the await, then I don't get an error, but I'm stuck with a Promise object...
Object.entries(sqlquerries).forEach(([queryName, queryTpl]) => {
try {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
} catch (err) {
console.error('An error occured running the query : ', err );
}
});
return report;
Why would that be? What can I do to construct my report object and get around this error?
Any help/pointers would be greatly appreciated.
javascript promise async-await
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
3
forEach(async ([
– Lawrence Cherone
Nov 22 '18 at 9:07
add a comment |
I have an object with a series of named SQL query templates that I'm trying to execute.
The query() method is async, so I should be able to run it with await, but I get an Unexpected identifier error. If I take off the await, then I don't get an error, but I'm stuck with a Promise object...
Object.entries(sqlquerries).forEach(([queryName, queryTpl]) => {
try {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
} catch (err) {
console.error('An error occured running the query : ', err );
}
});
return report;
Why would that be? What can I do to construct my report object and get around this error?
Any help/pointers would be greatly appreciated.
javascript promise async-await
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
I have an object with a series of named SQL query templates that I'm trying to execute.
The query() method is async, so I should be able to run it with await, but I get an Unexpected identifier error. If I take off the await, then I don't get an error, but I'm stuck with a Promise object...
Object.entries(sqlquerries).forEach(([queryName, queryTpl]) => {
try {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
} catch (err) {
console.error('An error occured running the query : ', err );
}
});
return report;
Why would that be? What can I do to construct my report object and get around this error?
Any help/pointers would be greatly appreciated.
javascript promise async-await
javascript promise async-await
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
asked Nov 22 '18 at 9:06
brainstormtrooperbrainstormtrooper
100211
100211
3
forEach(async ([
– Lawrence Cherone
Nov 22 '18 at 9:07
add a comment |
3
forEach(async ([
– Lawrence Cherone
Nov 22 '18 at 9:07
3
3
forEach(async ([– Lawrence Cherone
Nov 22 '18 at 9:07
forEach(async ([– Lawrence Cherone
Nov 22 '18 at 9:07
add a comment |
1 Answer
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Because the function await appears in (the forEach callback) isn't an async function. If you make it one, beware that forEach does nothing with the callback's return value, which will be a promise if it's an async function, and so you need to be sure to handle errors inline (which you're doing).
But, your return report suggests you're expecting to wait for this process to complete. Beware that forEach will not wait for the previous iteration's promise to resolve before proceeding with the next. If you want to do that, use the promise reduce trick instead and await the result (I assume this is all in an async function):
await Object.entries(sqlqueries).reduce((p, [queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
return p.then(async() => {
report[queryName] = await query(querystr);
});
}, Promise.resolve());
return report;
Or if you can run the queries in parallel, use map and Promise.all instead, and again await the result:
await Promise.all(Object.entries(sqlqueries).map(async ([queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
}));
return report;
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
1
Excellent!!! Not only is the answer just what I needed, but the analysis of the situation saved me my next question :-D Thanks loads!!!
– brainstormtrooper
Nov 22 '18 at 9:28
add a comment |
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1 Answer
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active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Because the function await appears in (the forEach callback) isn't an async function. If you make it one, beware that forEach does nothing with the callback's return value, which will be a promise if it's an async function, and so you need to be sure to handle errors inline (which you're doing).
But, your return report suggests you're expecting to wait for this process to complete. Beware that forEach will not wait for the previous iteration's promise to resolve before proceeding with the next. If you want to do that, use the promise reduce trick instead and await the result (I assume this is all in an async function):
await Object.entries(sqlqueries).reduce((p, [queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
return p.then(async() => {
report[queryName] = await query(querystr);
});
}, Promise.resolve());
return report;
Or if you can run the queries in parallel, use map and Promise.all instead, and again await the result:
await Promise.all(Object.entries(sqlqueries).map(async ([queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
}));
return report;
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
1
Excellent!!! Not only is the answer just what I needed, but the analysis of the situation saved me my next question :-D Thanks loads!!!
– brainstormtrooper
Nov 22 '18 at 9:28
add a comment |
Because the function await appears in (the forEach callback) isn't an async function. If you make it one, beware that forEach does nothing with the callback's return value, which will be a promise if it's an async function, and so you need to be sure to handle errors inline (which you're doing).
But, your return report suggests you're expecting to wait for this process to complete. Beware that forEach will not wait for the previous iteration's promise to resolve before proceeding with the next. If you want to do that, use the promise reduce trick instead and await the result (I assume this is all in an async function):
await Object.entries(sqlqueries).reduce((p, [queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
return p.then(async() => {
report[queryName] = await query(querystr);
});
}, Promise.resolve());
return report;
Or if you can run the queries in parallel, use map and Promise.all instead, and again await the result:
await Promise.all(Object.entries(sqlqueries).map(async ([queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
}));
return report;
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
1
Excellent!!! Not only is the answer just what I needed, but the analysis of the situation saved me my next question :-D Thanks loads!!!
– brainstormtrooper
Nov 22 '18 at 9:28
add a comment |
Because the function await appears in (the forEach callback) isn't an async function. If you make it one, beware that forEach does nothing with the callback's return value, which will be a promise if it's an async function, and so you need to be sure to handle errors inline (which you're doing).
But, your return report suggests you're expecting to wait for this process to complete. Beware that forEach will not wait for the previous iteration's promise to resolve before proceeding with the next. If you want to do that, use the promise reduce trick instead and await the result (I assume this is all in an async function):
await Object.entries(sqlqueries).reduce((p, [queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
return p.then(async() => {
report[queryName] = await query(querystr);
});
}, Promise.resolve());
return report;
Or if you can run the queries in parallel, use map and Promise.all instead, and again await the result:
await Promise.all(Object.entries(sqlqueries).map(async ([queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
}));
return report;
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
Because the function await appears in (the forEach callback) isn't an async function. If you make it one, beware that forEach does nothing with the callback's return value, which will be a promise if it's an async function, and so you need to be sure to handle errors inline (which you're doing).
But, your return report suggests you're expecting to wait for this process to complete. Beware that forEach will not wait for the previous iteration's promise to resolve before proceeding with the next. If you want to do that, use the promise reduce trick instead and await the result (I assume this is all in an async function):
await Object.entries(sqlqueries).reduce((p, [queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
return p.then(async() => {
report[queryName] = await query(querystr);
});
}, Promise.resolve());
return report;
Or if you can run the queries in parallel, use map and Promise.all instead, and again await the result:
await Promise.all(Object.entries(sqlqueries).map(async ([queryName, queryTpl]) => {
const querystr = replVars(queryTpl, vars);
report[queryName] = await query(querystr);
}));
return report;
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
answered Nov 22 '18 at 9:10
T.J. CrowderT.J. Crowder
690k12112251319
690k12112251319
1
Excellent!!! Not only is the answer just what I needed, but the analysis of the situation saved me my next question :-D Thanks loads!!!
– brainstormtrooper
Nov 22 '18 at 9:28
add a comment |
1
Excellent!!! Not only is the answer just what I needed, but the analysis of the situation saved me my next question :-D Thanks loads!!!
– brainstormtrooper
Nov 22 '18 at 9:28
1
1
Excellent!!! Not only is the answer just what I needed, but the analysis of the situation saved me my next question :-D Thanks loads!!!
– brainstormtrooper
Nov 22 '18 at 9:28
Excellent!!! Not only is the answer just what I needed, but the analysis of the situation saved me my next question :-D Thanks loads!!!
– brainstormtrooper
Nov 22 '18 at 9:28
add a comment |
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3
forEach(async ([– Lawrence Cherone
Nov 22 '18 at 9:07