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Recursive Dynamic Update DynamoDB (WIP)
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| import { NativeAttributeValue } from '@aws-sdk/util-dynamodb/src/models'; | |
| import { AttributeValue } from '@aws-sdk/client-dynamodb'; | |
| import { marshall } from '@aws-sdk/util-dynamodb'; | |
| interface DynamoUpdateParams { | |
| UpdateExpression: string; | |
| ExpressionAttributeNames: Record<string, string>; | |
| ExpressionAttributeValues: Record<string, AttributeValue>; | |
| } | |
| const attributeExtractor = (item: Record<string, unknown>) => Object.entries(item).reduce((previous, [key, value]): Record<string, string> => | |
| ({ | |
| ...previous, | |
| ...{ [`#${key}`]: key }, | |
| ...(typeof value === 'object' && value !== null && Object.keys(item).length > 0) && attributeExtractor(value as Record<string, unknown>) | |
| }), | |
| {}); | |
| const valueExtractor = (item: Record<string, NativeAttributeValue>) => Object.entries(item).reduce((previous, [key, value]): Record<string, string> => | |
| ({ | |
| ...previous, | |
| ...(typeof value !== 'object') && marshall({ [`:${key}`]: value }), | |
| ...(typeof value === 'object' && value !== null && Object.keys(item).length > 0) && valueExtractor(value as Record<string, unknown>) | |
| }), | |
| {}); | |
| const expressionCreator = (item: Record<string, unknown>, prefix: string|null) => | |
| Object.entries(item).reduce<string>((carry, [key, value]): string => { | |
| const prefixedKey = prefix ? `${prefix}.#${key}` : `#${key}`; | |
| if (typeof value === 'object' && value !== null && Object.keys(item).length > 0) { | |
| return `${carry}${expressionCreator(value as Record<string, unknown>, prefixedKey)}`; | |
| } | |
| return `${carry} ${prefixedKey} = :${key},`; | |
| }, ''); | |
| export const dynamicUpdateExpressionFromObject = <T extends { [K in keyof T]: NativeAttributeValue }>(item: T): DynamoUpdateParams => { | |
| const ExpressionAttributeNames: Record<string, string> = attributeExtractor(item); | |
| const ExpressionAttributeValues: Record<string, AttributeValue> = valueExtractor(item); | |
| const UpdateExpression = `SET${expressionCreator(item, null).slice(0, -1)}`; | |
| return { | |
| UpdateExpression, | |
| ExpressionAttributeNames, | |
| ExpressionAttributeValues, | |
| }; | |
| }; |
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