Custom decoder configuration in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a JSONDecoder instance.

iOS Swift

let decoder = [1]()

Drag options to blanks, or click blank then click option'

ADecoderConfig

BDecoder

CJSONEncoder

DJSONDecoder

Attempts:

3 left

💡 Hint

Common Mistakes

Using JSONEncoder instead of JSONDecoder.

Trying to instantiate Decoder which is a protocol.

Use JSONDecoder() to create a decoder for JSON data.

2fill in blank

medium

Complete the code to set the date decoding strategy to ISO8601.

iOS Swift

decoder.dateDecodingStrategy = [1]

Drag options to blanks, or click blank then click option'

A.formatted

B.iso8601

C.deferredToDate

D.secondsSince1970

Attempts:

3 left

💡 Hint

Common Mistakes

Using .formatted without a date formatter.

Choosing .secondsSince1970 which expects a timestamp.

Use .iso8601 to decode dates in ISO8601 format.

3fill in blank

hard

Fix the error in setting the key decoding strategy to convert from snake_case.

iOS Swift

decoder.keyDecodingStrategy = [1]

Drag options to blanks, or click blank then click option'

A.convertFromSnakeCase

B.useDefaultKeys

C.custom

D.convertToCamelCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using .useDefaultKeys which does no conversion.

Trying .convertToCamelCase which does not exist.

Use .convertFromSnakeCase to automatically convert snake_case keys to camelCase properties.

4fill in blank

hard

Fill both blanks to set the data decoding strategy to base64 and the non-conforming float decoding strategy to convert from string.

iOS Swift

decoder.dataDecodingStrategy = [1]
decoder.nonConformingFloatDecodingStrategy = [2]

Drag options to blanks, or click blank then click option'

A.base64

B.convertFromString

C.deferredToData

D.throw

Attempts:

3 left

💡 Hint

Common Mistakes

Using .deferredToData for data decoding which defers to Data's init.

Using .throw which causes decoding to fail on non-conforming floats.

Use .base64 for data decoding and .convertFromString for non-conforming floats from strings.

5fill in blank

hard

Fill all three blanks to create a JSONDecoder, set the key decoding strategy to convert from snake_case, and set the date decoding strategy to seconds since 1970.

iOS Swift

let decoder = [1]()
decoder.keyDecodingStrategy = [2]
decoder.dateDecodingStrategy = [3]

Drag options to blanks, or click blank then click option'

AJSONDecoder

B.convertFromSnakeCase

C.secondsSince1970

D.iso8601

Attempts:

3 left

💡 Hint

Common Mistakes

Using JSONEncoder instead of JSONDecoder.

Mixing up date decoding strategies.

Create JSONDecoder(), set keyDecodingStrategy to .convertFromSnakeCase, and dateDecodingStrategy to .secondsSince1970.