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Receiving null from childSnapshot.key

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0

This is how my database looks like:

 -members
 --L_C3OzCYFevhXzT5xk9 (specific key for Chat Room)
 ---user1: 'test@gmail.com'
 ---user2: 'test1@gmail.com'

I am trying to receive this specific key from Firebase and set it into the state. This is how I am trying to do that:

const query = firebase.database().ref('/members').orderByKey().equalTo(email);
 query.once('value')
 .then(function(snapshot) 
 snapshot.forEach(function(childSnapshot) 
 var key = childSnapshot.key;
 this.setState(ChatID: key);
 );
 );
 console.log(this.state.ChatID);

But every time I receive 'null' in console.log
What do I do wrong?

javascript react-native firebase-realtime-database react-native-firebase

share|improve this question

edited Mar 7 at 20:36

Doug Stevenson

81.2k997115

asked Mar 7 at 20:31

DrueTrueDrueTrue

579

add a comment | 

0

This is how my database looks like:

 -members
 --L_C3OzCYFevhXzT5xk9 (specific key for Chat Room)
 ---user1: 'test@gmail.com'
 ---user2: 'test1@gmail.com'

I am trying to receive this specific key from Firebase and set it into the state. This is how I am trying to do that:

const query = firebase.database().ref('/members').orderByKey().equalTo(email);
 query.once('value')
 .then(function(snapshot) 
 snapshot.forEach(function(childSnapshot) 
 var key = childSnapshot.key;
 this.setState(ChatID: key);
 );
 );
 console.log(this.state.ChatID);

But every time I receive 'null' in console.log
What do I do wrong?

javascript react-native firebase-realtime-database react-native-firebase

share|improve this question

edited Mar 7 at 20:36

Doug Stevenson

81.2k997115

asked Mar 7 at 20:31

DrueTrueDrueTrue

579

add a comment | 

This is how my database looks like:

 -members
 --L_C3OzCYFevhXzT5xk9 (specific key for Chat Room)
 ---user1: 'test@gmail.com'
 ---user2: 'test1@gmail.com'

I am trying to receive this specific key from Firebase and set it into the state. This is how I am trying to do that:

const query = firebase.database().ref('/members').orderByKey().equalTo(email);
 query.once('value')
 .then(function(snapshot) 
 snapshot.forEach(function(childSnapshot) 
 var key = childSnapshot.key;
 this.setState(ChatID: key);
 );
 );
 console.log(this.state.ChatID);

But every time I receive 'null' in console.log
What do I do wrong?

javascript react-native firebase-realtime-database react-native-firebase

share|improve this question

edited Mar 7 at 20:36

Doug Stevenson

81.2k997115

asked Mar 7 at 20:31

DrueTrueDrueTrue

579

 -members
 --L_C3OzCYFevhXzT5xk9 (specific key for Chat Room)
 ---user1: 'test@gmail.com'
 ---user2: 'test1@gmail.com'

const query = firebase.database().ref('/members').orderByKey().equalTo(email);
 query.once('value')
 .then(function(snapshot) 
 snapshot.forEach(function(childSnapshot) 
 var key = childSnapshot.key;
 this.setState(ChatID: key);
 );
 );
 console.log(this.state.ChatID);

share|improve this question

edited Mar 7 at 20:36

Doug Stevenson

81.2k997115

asked Mar 7 at 20:31

DrueTrueDrueTrue

579

share|improve this question

edited Mar 7 at 20:36

Doug Stevenson

81.2k997115

asked Mar 7 at 20:31

DrueTrueDrueTrue

579

edited Mar 7 at 20:36

Doug Stevenson

81.2k997115

edited Mar 7 at 20:36

Doug Stevenson

81.2k997115

asked Mar 7 at 20:31

DrueTrueDrueTrue

579

asked Mar 7 at 20:31

DrueTrueDrueTrue

579

1 Answer
1

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1

The query is asynchronous and returns a promise that resolves some time later. Your log message is executing before that query finishes. You can only use the results of the query after the promise resolves and your then() callback is invoked.

share|improve this answer

answered Mar 7 at 20:35

Doug StevensonDoug Stevenson

81.2k997115

add a comment | 

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1

The query is asynchronous and returns a promise that resolves some time later. Your log message is executing before that query finishes. You can only use the results of the query after the promise resolves and your then() callback is invoked.

share|improve this answer

answered Mar 7 at 20:35

Doug StevensonDoug Stevenson

81.2k997115

add a comment | 

1

The query is asynchronous and returns a promise that resolves some time later. Your log message is executing before that query finishes. You can only use the results of the query after the promise resolves and your then() callback is invoked.

share|improve this answer

answered Mar 7 at 20:35

Doug StevensonDoug Stevenson

81.2k997115

add a comment | 

The query is asynchronous and returns a promise that resolves some time later. Your log message is executing before that query finishes. You can only use the results of the query after the promise resolves and your then() callback is invoked.

share|improve this answer

answered Mar 7 at 20:35

Doug StevensonDoug Stevenson

81.2k997115

share|improve this answer

answered Mar 7 at 20:35

Doug StevensonDoug Stevenson

81.2k997115

answered Mar 7 at 20:35

Doug StevensonDoug Stevenson

81.2k997115

answered Mar 7 at 20:35

Doug StevensonDoug Stevenson

81.2k997115