# Values

Factory class for attribute value assignments.

- Source: [`aws-appsync/lib/key.ts`](https://github.com/aws/aws-cdk/blob/v2.275.0/packages/aws-cdk-lib/aws-appsync/lib/key.ts#L239)
- Type last changed: v2.60.0 · 12 Jan 2023

## Example

```ts
const api = new appsync.GraphqlApi(this, 'Api', {
  name: 'demo',
  definition: appsync.Definition.fromFile(path.join(__dirname, 'schema.graphql')),
  authorizationConfig: {
    defaultAuthorization: {
      authorizationType: appsync.AuthorizationType.IAM,
    },
  },
  xrayEnabled: true,
});

const demoTable = new dynamodb.Table(this, 'DemoTable', {
  partitionKey: {
    name: 'id',
    type: dynamodb.AttributeType.STRING,
  },
});

const demoDS = api.addDynamoDbDataSource('demoDataSource', demoTable);

// Resolver for the Query "getDemos" that scans the DynamoDb table and returns the entire list.
// Resolver Mapping Template Reference:
// https://docs.aws.amazon.com/appsync/latest/devguide/resolver-mapping-template-reference-dynamodb.html
demoDS.createResolver('QueryGetDemosResolver', {
  typeName: 'Query',
  fieldName: 'getDemos',
  requestMappingTemplate: appsync.MappingTemplate.dynamoDbScanTable(),
  responseMappingTemplate: appsync.MappingTemplate.dynamoDbResultList(),
});

// Resolver for the Mutation "addDemo" that puts the item into the DynamoDb table.
demoDS.createResolver('MutationAddDemoResolver', {
  typeName: 'Mutation',
  fieldName: 'addDemo',
  requestMappingTemplate: appsync.MappingTemplate.dynamoDbPutItem(
    appsync.PrimaryKey.partition('id').auto(),
    appsync.Values.projecting('input'),
  ),
  responseMappingTemplate: appsync.MappingTemplate.dynamoDbResultItem(),
});

//To enable DynamoDB read consistency with the `MappingTemplate`:
demoDS.createResolver('QueryGetDemosConsistentResolver', {
  typeName: 'Query',
  fieldName: 'getDemosConsistent',
  requestMappingTemplate: appsync.MappingTemplate.dynamoDbScanTable(true),
  responseMappingTemplate: appsync.MappingTemplate.dynamoDbResultList(),
});
```

## Initializer

```ts
new Values()
```

## Methods

- `attribute(attr: string): AttributeValuesStep` (static) — Allows assigning a value to the specified attribute.

- `projecting(arg?: string): AttributeValues` (static) — Treats the specified object as a map of assignments, where the property names represent attribute names.

  It’s opinionated about how it represents
  some of the nested objects: e.g., it will use lists (“L”) rather than sets
  (“SS”, “NS”, “BS”). By default it projects the argument container ("$ctx.args").