如何列出Cloud Firestore文档中的子集合

时间:2017-10-06 00:15:05

标签: javascript firebase google-cloud-firestore

假设我将此最小数据库存储在Cloud Firestore中。如何检索subCollection1subCollection2

的名称
rootCollection {
    aDocument: {
        someField: { value: 1 },
        anotherField: { value: 2 }
        subCollection1: ...,
        subCollection2: ...,
    }
}

我希望能够只读取aDocument之外的ID,但只有当我get()文档时才显示字段。

rootRef.doc('aDocument').get()
  .then(doc =>

    // only logs [ "someField", "anotherField" ], no collections
    console.log( Object.keys(doc.data()) )
  )

3 个答案:

答案 0 :(得分:4)

在Node.js中,您将使用'ListCollectionIds'方法

var firestore = require('firestore.v1beta1');

var client = firestore.v1beta1({
  // optional auth parameters.
});

// Iterate over all elements.
var formattedParent = client.anyPathPath("[PROJECT]", "[DATABASE]", "[DOCUMENT]", "[ANY_PATH]");

client.listCollectionIds({parent: formattedParent}).then(function(responses) {
    var resources = responses[0];
    for (var i = 0; i < resources.length; ++i) {
        // doThingsWith(resources[i])
    }
})
.catch(function(err) {
    console.error(err);
});

客户端SDK(Web,iOS,Android)目前不支持此功能。

答案 1 :(得分:2)

他们似乎已向Node.js添加了一个名为getCollections()的方法:

firestore.doc(`/myCollection/myDocument`).getCollections().then(collections => {
  for (let collection of collections) {
    console.log(`Found collection with id: ${collection.id}`);
  }
});

此示例在/myCollection/myDocument

打印出文档的所有子集合

答案 2 :(得分:0)

the documentation

中是否详细说明了这一点
/**
 * Delete a collection, in batches of batchSize. Note that this does
 * not recursively delete subcollections of documents in the collection
 */
function deleteCollection(db, collectionRef, batchSize) {
    var query = collectionRef.orderBy('__name__').limit(batchSize);

    return new Promise(function(resolve, reject) {
        deleteQueryBatch(db, query, batchSize, resolve, reject);
    });
}

function deleteQueryBatch(db, query, batchSize, resolve, reject) {
    query.get()
        .then((snapshot) => {
            // When there are no documents left, we are done
            if (snapshot.size == 0) {
                return 0;
            }

            // Delete documents in a batch
            var batch = db.batch();
            snapshot.docs.forEach(function(doc) {
                batch.delete(doc.ref);
            });

            return batch.commit().then(function() {
                return snapshot.size;
            });
        }).then(function(numDeleted) {
            if (numDeleted <= batchSize) {
                resolve();
                return;
            }

            // Recurse on the next process tick, to avoid
            // exploding the stack.
            process.nextTick(function() {
                deleteQueryBatch(db, query, batchSize, resolve, reject);
            });
        })
        .catch(reject);
}