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    Function makeIdempotent

    • Function wrapper to make any function idempotent.

      The makeIdempotent function is a higher-order function that takes another function and returns a new version of that function with idempotency behavior. This means that if the function is called multiple times with the same input, it will return the same result without re-executing the original function logic.

      By default, the entire first argument is hashed to create the idempotency key. You can customize this behavior:

      Using a subset of the payload

      Type Parameters

      Parameters

      Returns (...args: Parameters<Func>) => ReturnType<Func>

      import { makeIdempotent, IdempotencyConfig } from '@aws-lambda-powertools/idempotency';
      import { DynamoDBPersistenceLayer } from '@aws-lambda-powertools/idempotency/dynamodb';

      const processRecord = (record: Record<string, unknown>): unknown => {
        // your processing logic
        return result;
      };

      const processIdempotently = makeIdempotent(processRecord, {
        persistenceStore: new DynamoDBPersistenceLayer({ tableName: 'idempotency-table' }),
        config: new IdempotencyConfig({
          eventKeyJmesPath: 'transactionId', // hash only this field as idempotency key
        }),
      });

      export const handler = async (event: { records: Record<string, unknown>[] }) => {
       for (const record of event.records) {
         // use the idempotent function
         const result = await processIdempotently(record);
         // ... do something with the result
        }
      };

      Using a different function argument (useful for multi-parameter functions)

      import { makeIdempotent } from '@aws-lambda-powertools/idempotency';
      import { DynamoDBPersistenceLayer } from '@aws-lambda-powertools/idempotency/dynamodb';

      const processRecord = (record: Record<string, unknown>, userId: string): unknown => {
        // your processing logic
        return result;
      };

      const processIdempotently = makeIdempotent(processRecord, {
        persistenceStore: new DynamoDBPersistenceLayer({ tableName: 'idempotency-table' }),
        dataIndexArgument: 1, // hash the userId (second argument) instead of first (record)
      });

      export const handler = async (event: { records: Record<string,unknown>[]; userId: string }) => {
       for (const record of event.records) {
         const userId = event.userId;
         // use the idempotent function
         const result = await processIdempotently(record, userId);
         // ... do something with the result
        }
      };

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