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

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

import { isFunction, isUndefined } from "@nerdware/ts-type-safety-utils";
/**
 * This `IOAction` uses `transformValue` functions (if defined) to transform
 * attribute values before they are validated, converted to DynamoDB types, etc.
 */
export const transformValues = function (item, { schemaEntries, ioDirection, ...ctx }) {
    // To avoid mutating the original item, create a new object to return
    const itemToReturn = { ...item };
    // Iterate over schemaEntries
    for (let i = 0; i < schemaEntries.length; i++) {
        const [attrName, attrConfig] = schemaEntries[i];
        // See if a transformValue fn is defined
        const transformValue = attrConfig.transformValue?.[ioDirection];
        // If schema has transformValue toDB/fromDB, pass the existing value into the fn
        if (Object.hasOwn(itemToReturn, attrName) && isFunction(transformValue)) {
            // Get new value; any type mismatches are caught later by the `typeChecking` method
            const transformedValue = transformValue(itemToReturn[attrName]);
            // If transformedValue is not undefined, add it to itemToReturn
            if (!isUndefined(transformedValue))
                itemToReturn[attrName] = transformedValue;
        }
        // Run recursively on nested attributes if parent value exists
        if (attrConfig.schema && Object.hasOwn(itemToReturn, attrName)) {
            itemToReturn[attrName] = this.recursivelyApplyIOAction(this.transformValues, itemToReturn[attrName], {
                parentItem: itemToReturn,
                ioDirection,
                ...ctx,
                schema: attrConfig.schema, // <-- overwrites ctx.schema with the nested schema
            });
        }
    }
    return itemToReturn;
};