javascript source code of index

import { DynamoDB } from "aws-sdk";
import { compose, curry, flatten, join, map, mergeAll, pluck, splitEvery, toPairs } from "ramda";
import * as P from "~/shared/promise";

const DYNAMO_DB_MAX_BATCH_SIZE = 25;
const splitBatches = splitEvery(DYNAMO_DB_MAX_BATCH_SIZE);

export function createEnhancedClient() {
  const params = process.env.IS_LOCAL
    ? {
        region: "localhost",
        endpoint: "http://localhost:8000",
      }
    : {};

  const client = new DynamoDB.DocumentClient(params);

  const writeSingleBatch = curry(function _writeSingleBatch(tableName, batch) {
    return client
      .batchWrite({
        RequestItems: {
          [tableName]: batch,
        },
      })
      .promise();
  });

  const writeAllBatches = function _writeAllBatches(tableName, items) {
    return compose(map(writeSingleBatch(tableName)), splitBatches)(items);
  };

  const batchWrite = curry(async function _batchWrite(tableName, items) {
    return flatten(await P.all(writeAllBatches(tableName, items)));
  });

  return {
    client,
    batchWrite,
  };
}

const buildGenericConditionExpression = curry(function _buildGenericConditionExpression(exprAttr, obj) {
  const buildDescriptors = compose(
    map(([key, value]) => ({
      expr: `#${key} = :${key}`,
      name: { [`#${key}`]: key },
      value: { [`:${key}`]: value },
    })),
    toPairs
  );
  const descriptors = buildDescriptors(obj);

  const buildExpression = compose(join(" and "), pluck("expr"));
  const buildAttrNames = compose(mergeAll, pluck("name"));
  const buildAttrValues = compose(mergeAll, pluck("value"));

  const expression = buildExpression(descriptors);
  const attrNames = buildAttrNames(descriptors);
  const attrValues = buildAttrValues(descriptors);

  return {
    [exprAttr]: expression,
    ExpressionAttributeNames: attrNames,
    ExpressionAttributeValues: attrValues,
  };
});

export const buildKeyConditionExpression = buildGenericConditionExpression("KeyConditionExpression");

export const buildConditionExpression = buildGenericConditionExpression("ConditionExpression");

export function buildSetUpdateExpression(obj) {
  const buildDescriptors = compose(
    map(([key, value]) => ({
      expr: `#${key} = :${key}`,
      name: { [`#${key}`]: key },
      value: { [`:${key}`]: value },
    })),
    toPairs
  );
  const descriptors = buildDescriptors(obj);

  const buildExpression = compose((expr) => `SET ${expr}`, join(", "), pluck("expr"));
  const buildAttrNames = compose(mergeAll, pluck("name"));
  const buildAttrValues = compose(mergeAll, pluck("value"));

  const expression = buildExpression(descriptors);
  const attrNames = buildAttrNames(descriptors);
  const attrValues = buildAttrValues(descriptors);

  return {
    UpdateExpression: expression,
    ExpressionAttributeNames: attrNames,
    ExpressionAttributeValues: attrValues,
  };
}