node-redis/packages/client/lib/commands/XREAD.ts

import { RedisCommandArgument, RedisCommandArguments } from '.';

export const FIRST_KEY_INDEX = (streams: Array<XReadStream> | XReadStream): RedisCommandArgument => {
    return Array.isArray(streams) ? streams[0].key : streams.key;
};

export const IS_READ_ONLY = true;

interface XReadStream {
    key: RedisCommandArgument;
    id: RedisCommandArgument;
}

interface XReadOptions {
    COUNT?: number;
    BLOCK?: number;
}

export function transformArguments(
    streams: Array<XReadStream> | XReadStream,
    options?: XReadOptions
): RedisCommandArguments {
    const args: RedisCommandArguments = ['XREAD'];

    if (options?.COUNT) {
        args.push('COUNT', options.COUNT.toString());
    }

    if (typeof options?.BLOCK === 'number') {
        args.push('BLOCK', options.BLOCK.toString());
    }

    args.push('STREAMS');

    const streamsArray = Array.isArray(streams) ? streams : [streams],
        argsLength = args.length;
    for (let i = 0; i < streamsArray.length; i++) {
        const stream = streamsArray[i];
        args[argsLength + i] = stream.key;
        args[argsLength + streamsArray.length + i] = stream.id;
    }

    return args;
}

export { transformStreamsMessagesReply as transformReply } from './generic-transformers';