export function reduceOutputs(
outputs: List<ImmutableOutput> = List(),
output: OnDiskOutput
): List<ImmutableOutput> {
// Find the last output to see if it's a stream type
// If we don't find one, default to null
const last = outputs.last(null);
if (!last || !last.output_type) {
return outputs.push(createImmutableOutput(output));
}
if (output.output_type !== "stream" || last.output_type !== "stream") {
// If the last output type or the incoming output type isn't a stream
// we just add it to the outputs
// This is kind of like a "break" between streams if we get error,
// display_data, execute_result, etc.
return outputs.push(createImmutableOutput(output));
}
const streamOutput: OnDiskStreamOutput = output;
if (typeof streamOutput.name === "undefined") {
return outputs.push(createImmutableOutput(streamOutput));
}
function appendText(text: string): string {
if (typeof streamOutput.text === "string") {
return escapeCarriageReturnSafe(text + streamOutput.text);
}
return text;
}
// Invariant: size > 0, outputs.last() exists
if (last.name === streamOutput.name) {
return outputs.updateIn([outputs.size - 1, "text"], appendText);
}
// Check if there's a separate stream to merge with
const nextToLast = outputs.butLast().last(null);
if (
nextToLast &&
nextToLast.output_type === "stream" &&
nextToLast.name === streamOutput.name
) {
return outputs.updateIn([outputs.size - 2, "text"], appendText);
}
// If nothing else matched, just append it
return outputs.push(createImmutableOutput(streamOutput));
}