smartstream/ts/smartstream.functions.ts
2023-11-03 23:25:00 +01:00

26 lines
815 B
TypeScript

import { Transform, type TransformCallback, type TransformOptions } from 'stream';
export interface AsyncTransformFunction<TInput, TOutput> {
(chunkArg: TInput): Promise<TOutput>;
}
export function createTransformFunction<TInput, TOutput>(
asyncFunction: AsyncTransformFunction<TInput, TOutput>,
options?: TransformOptions
): Transform {
const transformStream = new Transform({
...options,
objectMode: true, // Ensure we operate in object mode
async transform(chunk: TInput, encoding: string, callback: TransformCallback) {
try {
const transformed = await asyncFunction(chunk);
this.push(transformed);
callback();
} catch (error) {
callback(error instanceof Error ? error : new Error(String(error)));
}
}
});
return transformStream;
}