DataLoader batching and caching in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new DataLoader instance.

GraphQL

const userLoader = new DataLoader([1]);

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AbatchLoadFn

BmaxBatchSize

CcacheMap

DcacheKeyFn

Attempts:

3 left

💡 Hint

Common Mistakes

Using cacheMap instead of batchLoadFn

Trying to pass maxBatchSize as the first argument

Confusing cacheKeyFn with batchLoadFn

The batchLoadFn is the required function that DataLoader uses to batch and load keys.

2fill in blank

medium

Complete the code to load a user by ID using DataLoader.

GraphQL

userLoader.[1](userId);

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AloadMany

Bclear

CbatchLoadFn

Dload

Attempts:

3 left

💡 Hint

Common Mistakes

Using loadMany when loading a single key

Trying to call batchLoadFn directly

Using clear instead of load

The load method loads a single key and returns a Promise for the value.

3fill in blank

hard

Fix the error in clearing the cache for a specific key.

GraphQL

userLoader.[1](userId);

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AclearAll

Bclear

Cprime

Dload

Attempts:

3 left

💡 Hint

Common Mistakes

Using clearAll to clear a single key

Using prime instead of clear

Calling load instead of clearing

The clear method removes a specific key from the cache.

4fill in blank

hard

Fill both blanks to add a new value to the cache and then clear it.

GraphQL

userLoader.[1](userId, userData);
userLoader.[2](userId);

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Aprime

Bclear

Cload

DclearAll

Attempts:

3 left

💡 Hint

Common Mistakes

Using load instead of prime to add cache

Using clearAll instead of clear to remove one key

Swapping the order of methods

prime adds a key-value pair to the cache. clear removes a specific key from the cache.

5fill in blank

hard

Fill all three blanks to batch load multiple keys and then clear the entire cache.

GraphQL

userLoader.[1](userIds);
userLoader.[2]();
userLoader.[3](userId);

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AloadMany

BclearAll

Cclear

Dload

Attempts:

3 left

💡 Hint

Common Mistakes

Using load instead of loadMany for multiple keys

Using clear instead of clearAll to clear all cache

Mixing up clear and clearAll

loadMany loads multiple keys at once. clearAll clears the entire cache. clear clears a specific key.