spridev
commented
2 years ago Here are some existing JS/TS alternatives, using different approaches and syntaxes:
- https://github.com/awslabs/dynamodb-data-mapper-js/tree/master/packages/dynamodb-expressions
- https://github.com/faceteer/expression-builder
- https://gitlab.com/monster-space-network/typemon/dynamon
Looking at the existing official solutions above, I do personally like the builder pattern used in Java. This reminds me of the usual SQL query builders like Laravel Eloquent or Knex.js. Chainable methods, clean syntax, easy to understand.
Finally, I would rather not wrap the DynamoDBClient within another class, with a magic update method for example (like in Dynamon). I feel like the following approach gives more flexibility and control to the user:
const expr = new ExpressionBuilder().buildForUpdate();
const response = await ddb.send(
new UpdateItemCommand({
TableName: TABLE_NAME,
Key: marshall({
PK: 'USER#1234',
SK: 'USER#1234',
}),
// Solution 1
UpdateExpression: expr.content,
ExpressionAttributeNames: expr.names,
ExpressionAttributeValues: expr.values,
// Solution 2
...expr
})
);Is this feature still pending or already in the roadmap? I think it's an important missing piece for the DynamoDB DX. Once the syntax has been determined, I will try to implement it, either here or as an independent package.
github-actions[bot]
Is your feature request related to a problem? Please describe.
Many other AWS SDKs provide abstractions for DynamoDB expressions. They are more intuitive by providing mapping from variables to expression, and they also handle the encoding. Some examples from other AWS SDKs:
Currently the closest library provided by SDK team is the Expression package in DynamoDB data mapper, but it is more of a building block for the data mapper, with confusing interface for public consumption.
Describe the solution you'd like
Provide an expression builder similar to example above.
Issues: