arrayValueFix.ts

// arrayValue doesn't work in rds-data-client, even though it's part of the documentation. Just says "not supported"
// https://github.com/aws/aws-sdk/issues/9#issuecomment-1104182976

type ExecuteStatementCommandInput_ = Pick<ExecuteStatementCommandInput, 'sql' | 'parameters'>
  
// TODO support multiple datatypes (currently only supports string)
arrayValueFix({sql, parameters}: ExecuteStatementCommandInput_): ExecuteStatementCommandInput_ {
  let fixedSql = sql
  let fixedParameters: ExecuteStatementCommandInput["parameters"] = []
  let offset = 0
  parameters.forEach((parameter, i) => {
    if (!parameter.value.arrayValue) {
      fixedParameters.push(parameter)
      return // all good, carry on
    }
    const values = parameter.value.arrayValue.stringValues
    if (!values) {
      throw "Currently only applied arrayValue for stringValues. Fix this if need other array value-types"
    }
    const paramsSeparate = values.map((value, idx) => ({
      name: `id${idx + offset}`,
      value: {stringValue: value},
      typeHint: parameter.typeHint
    }))
    // @ts-ignore
    const placeholder = [...Array(values.length).keys()]
      .map(idx => `:id${idx + offset}`).join(',')
    offset += values.length
    fixedSql = fixedSql.replace(
      `:${parameter.name}`,
      `(${placeholder})`
    )
    fixedParameters = [...fixedParameters, ...paramsSeparate]
  })
  return {sql: fixedSql, parameters: fixedParameters}
}
  
async function executeStatement<O = object>(statement: ExecuteStatementCommandInput_): Promise<O[]> {
  const {sql, parameters} = this.arrayValueFix(statement)
  const response = await rdsClient.executeStatement({
    includeResultMetadata: true,
    secretArn: RDS.db.secretArn,
    resourceArn: RDS.db.clusterArn,
    database: RDS.db.defaultDatabaseName,
    sql,
    parameters
  })    
}
  
  
// Run like this
// -------------------
const tags = await db.executeStatement<Tag>({
  sql: `select * from tags where id in :tids and user_id=:user_id`,
  parameters: [
    {name: "tids", typeHint: "UUID", value: {arrayValue: {stringValues: tids}}},
    {name: "user_id", typeHint: "UUID", value: {stringValue: context.user.id}}
  ]
})