@nerdware/ddb-single-table/dist/esm/IOActions/aliasMapping.js

A schema-based DynamoDB modeling tool, high-level API, and type-generator built to supercharge single-table designs!⚡

import { hasKey } from "@nerdware/ts-type-safety-utils";
import { ItemInputError } from "../utils/index.js";
/**
 * This `IOAction` swaps attribute-names with their corresponding aliases:
 * - `toDB`: replaces "alias" keys with attribute names
 * - `fromDB`: replaces attribute names with "alias" keys
 *
 * @throws {ItemInputError} If an attribute is not defined in the schema, and `allowUnknownAttributes` is not `true`.
 */
export const aliasMapping = function (item, { aliasesMap, modelName, schema, schemaOptions: { allowUnknownAttributes } }) {
    const itemToReturn = {};
    // Iterate over the item's keys
    for (const itemKey in item) {
        if (hasKey(aliasesMap, itemKey)) {
            // If itemKey is in the aliasMap, update the item with the mapped key
            itemToReturn[aliasesMap[itemKey]] = item[itemKey];
        }
        else if (hasKey(schema, itemKey)
            || allowUnknownAttributes === true
            || (Array.isArray(allowUnknownAttributes) && allowUnknownAttributes.includes(itemKey))) {
            // Else if itemKey is an attribute OR schema allows the unknown attribute, simply add K-V as-is
            itemToReturn[itemKey] = item[itemKey];
        }
        else {
            throw new ItemInputError(`${modelName} item contains unknown property: "${itemKey}"`);
        }
    }
    return itemToReturn;
};