Type alias CompositeCondition

A filter or condition expression. This type serves as the root of a object structure for specifying a filter/condition expression which is translated to a DynamoDB Conditional expression for use with some of the available operations (in their underlying ConditionExpression or FilterExpression fields.

The syntax is very similar to Mongo's query syntax, but a little bit stricter to help with type evaluation.

A simple condition expression consists of key paths mapped to an operator. For example, to test profile.username = 'test@example.com', you would construct an expression as follows:

{
  'profile.username': { $eq: 'test@example.com' },
}
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This expression would be translated to DynamoDB's FilterExpression syntax as:

#attr0.username = :value0

(profile is a reserved word in DynamoDB and automatically mapped. #attr0 and :value0 will be written to ExpressionAttributeNames and ExpressionAttributeValues respectively for you).

Multiple key paths in the same object are treated as an AND operation implicitly.

• NOTE: For a full list of key path operators, see the [[KeyPathsAndClause]] type.

You can also construct AND, OR and NOT expressions for more complex evaluations, e.g.:

{
  $or: [
  { $not: { 'location.value': { $lte: 0 } } },
  {
     $and: [
       { 'location.point.x': { $gt: 10 } },
       { 'location.point.y': { $gt: 1.3 } },
     ],
  }
  ],
};
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This would be written in DynamoDB's FilterExpression syntax as:

(NOT #attr0.#attr1 <= :value0) OR (#attr0.point.x > :value1 AND #attr0.point.y < :value2)

where:

• #attr0 is mapped to 'location' (reserved word)
• #attr1 is mapped to 'value' (reserved word)
• :value0 is mapped to 0 (Expression Attribute Value)
• :value1 is mapped to 10 (Expression Attribute Value)
• :value2 is mapped to 1.3 (Expression Attribute Value)