@aws-lambda-powertools/commons/lib/esm/unmarshallDynamoDB.js

A shared utility package for Powertools for AWS Lambda (TypeScript) libraries

class UnmarshallDynamoDBAttributeError extends Error {
    constructor(message) {
        super(message);
        this.name = 'UnmarshallDynamoDBAttributeError';
    }
}
// biome-ignore lint/suspicious/noExplicitAny: we need to use any here to support the different types of DynamoDB attributes
const typeHandlers = {
    NULL: () => null,
    S: (value) => value,
    B: (value) => value,
    BS: (value) => new Set(value),
    SS: (value) => new Set(value),
    BOOL: (value) => Boolean(value),
    N: (value) => convertNumber(value),
    NS: (value) => new Set(value.map(convertNumber)),
    L: (value) => value.map(convertAttributeValue),
    M: (value) => Object.entries(value).reduce((acc, [key, value]) => {
        acc[key] = convertAttributeValue(value);
        return acc;
    }, {}),
};
const convertAttributeValue = (data) => {
    const [type, value] = Object.entries(data)[0];
    if (value !== undefined) {
        const handler = typeHandlers[type];
        if (!handler) {
            throw new UnmarshallDynamoDBAttributeError(`Unsupported type passed: ${type}`);
        }
        return handler(value);
    }
    throw new UnmarshallDynamoDBAttributeError(`Value is undefined for type: ${type}`);
};
const convertNumber = (numString) => {
    const num = Number(numString);
    const infinityValues = [Number.POSITIVE_INFINITY, Number.NEGATIVE_INFINITY];
    const isLargeFiniteNumber = (num > Number.MAX_SAFE_INTEGER || num < Number.MIN_SAFE_INTEGER) &&
        !infinityValues.includes(num);
    if (isLargeFiniteNumber) {
        try {
            return BigInt(numString);
        }
        catch {
            throw new UnmarshallDynamoDBAttributeError(`${numString} can't be converted to BigInt`);
        }
    }
    return num;
};
/**
 * Unmarshalls a DynamoDB AttributeValue to a JavaScript object.
 *
 * The implementation is loosely based on the official AWS SDK v3 unmarshall function but
 * without support the customization options and with assumed support for BigInt.
 *
 * @param data - The DynamoDB AttributeValue to unmarshall
 */
const unmarshallDynamoDB = (data
// @ts-expect-error - We intentionally wrap the data into a Map to allow for nested structures
) => convertAttributeValue({ M: data });
export { unmarshallDynamoDB, UnmarshallDynamoDBAttributeError };