Make an end date parameter in DynamoDB optional?

Question

Currently we have it set up such that the start date and end date are required to query results, looking something like this.

interface GetStuffIdArgs extends DdbPaginationQueryArgs {
  // Required query params
  startTime: string;
  endTime: string;

async getOtherStuff(id: string | number, args: GetOtherStuffIdArgs) {
    const { startTime, endTime, id, someType, order = "DESC" } = args;

    // convert times to ISO (utc 0);
    const startTimeISO = new Date(startTime).toISOString();
    const endTimeISO = new Date(endTime).toISOString();

      /**
       * Query between start and end time
       */
      KeyConditionExpression: `${this.PK} = :pk and ${this.SK} BETWEEN :starttime AND :endtime`

I've tried a few things that I thought could make the parameter optional but am not sure how the query itself would change based off of it.

interface GetStuffIdArgs extends DdbPaginationQueryArgs {
  // Required query params
  startTime: string;
  endTime: string | null;

  async getOtherStuff(id: string | number, args: GetOtherStuffIdArgs) {
    const { startTime, endTime, id, someType, order = "DESC" } = args;

    // convert times to ISO (utc 0);
    const startTimeISO = new Date(startTime).toISOString();
    const endTimeISO = endTime ? new Date(endTime).toISOString() : null;

If this is even the correct way, I'm not quite sure how to make the query change based off of it.

First time I've ever looked at dynamodb. I'm curious how I can make the :et optional such that if it is null, it will simply query everything from the start date and on? Perhaps the better question would be: is it possible to make the KeyConditionExpression conditional such that it could be one of two things depending on params?

score 0 · Answer 1 · answered Apr 13 '21 at 18:16

If the data is historical (always in the past) you could just do this:

const endTimeISO = endTime ? new Date(endTime).toISOString() : new Date().toISOString();

If the date may be in the future you'd just need to use a date beyond the max.

const endTimeISO = endTime ? new Date(endTime).toISOString() : new Date(8640000000000000).toISOString();

(according to this post the above is the max date value for JS)

Make an end date parameter in DynamoDB optional?

1 Answers1