> ## Documentation Index
> Fetch the complete documentation index at: https://cdktn.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Upgrading to CDKTF Version 0.10

> We changed how lists of computed attributes work to allow referencing the whole list

0.10 includes improvements to the provider code bindings, to allow referencing lists of computed attributes as a whole list instead of just individual items of that list.
We also shipped a lot of CLI improvements in 0.10, including support for multiple stacks in `cdktf deploy`, `cdktf output`, and `cdktf destroy`.

### Remove `cdktf synth --json` Option

PR: [#1640](https://github.com/open-constructs/cdk-terrain/pull/1640)

If you are using `cdktf synth --json <stack-name>` to get the synthesized JSON configuration for your Stack, you will now need to run `cdktf synth && cat ./cdktf.out/stacks/<stack-name>/cdk.tf.json` instead. The `./cdktf.out` part is your output directory (set by `cdktf.json` or via the `--output` flag).

### Model ComplexComputedLists as ComplexLists and ComputedObjects

PR: [#1499](https://github.com/open-constructs/cdk-terrain/pull/1499)

In an effort to streamline the interfaces of resources, computed attributes of the type list and set are now modeled as a separate `ComplexList` type instead of being a method that directly takes an index and returns an item. This change also did change the type of the index from `string` to `number`.

#### Typescript

```typescript theme={null}
// previously
const firstItemId = resource.listAttribute("0").id;

// new
const firstItemId = resource.listAttribute.get(0).id;
const firstItem = resource.listAttribute.get(0); // now possible
```

#### Python

```python theme={null}
# previously
first_item_id = resource.list_attribute("0").id;

# new
first_item_id = resource.list_attribute.get(0).id;
first_item = resource.list_attribute.get(0); # now possible
```

#### CSharp

```csharp theme={null}
// previously
string firstItemId = resource.ListAttribute("0").Id;

// new
string firstItemId = resource.ListAttribute.Get(0).Id;
ListAttributeItem firstItem = resource.ListAttribute.Get(0); // now possible
```

#### Java

```java theme={null}
// previously
String firstItemId = resource.listAttribute("0").getId();

// new
String firstItemId = resource.getListAttribute().get(0).getId();
ListAttributeItem firstItem = resource.getListAttribute().get(0); // now possible
```

#### Go

```golang theme={null}
// previously
firstItemId := resource.ListAttribute(jsii.String("0")).Id();

// new
firstItemId := resource.ListAttribute().Get(jsii.Number(0)).Id();
firstItem := resource.ListAttribute().Get(jsii.Number(0)); // now possible
```

### Referencing computed string map entries via function call

PR: [#1630](https://github.com/open-constructs/cdk-terrain/pull/1630)

In preparation for a similar change as to the computed lists, string map entries can now be accessed via a function call instead of using `Fn.lookup`. Accessing the whole map at once now requires a different function call in the meantime.

#### Example

```typescript theme={null}
const bucket = new s3.S3Bucket(this, "bucket");

// previously
const firstRuleStage = Fn.lookup(
  bucket.lifecycleRule("0").tags,
  "stage",
  "no-stage",
);
const firstRuleTags = bucket.lifecycleRule("0").tags;

// new
const firstRuleStage = bucket.lifecycleRule.get(0).tags("stage"); // tags is now a function
const firstRuleTags = bucket.lifecycleRule
  .get(0)
  .interpolationForAttribute("tags"); // will be improved in a future iteration
```