transaction.ts

import { wrapMultiResult, noop } from "./utils";
import asCallback from "standard-as-callback";
import Pipeline from "./Pipeline";
import { Callback } from "./types";
import { ChainableCommander } from "./utils/RedisCommander";

export interface Transaction {
  pipeline(commands?: string[]): ChainableCommander;
  multi(options: { pipeline: false }): Promise<"OK">;
  multi(): ChainableCommander;
  multi(options: { pipeline: true }): ChainableCommander;
  multi(commands?: string[]): ChainableCommander;
}

export function addTransactionSupport(redis) {
  redis.pipeline = function (commands) {
    const pipeline = new Pipeline(this);
    if (Array.isArray(commands)) {
      pipeline.addBatch(commands);
    }
    return pipeline;
  };

  const { multi } = redis;
  redis.multi = function (commands, options) {
    if (typeof options === "undefined" && !Array.isArray(commands)) {
      options = commands;
      commands = null;
    }
    if (options && options.pipeline === false) {
      return multi.call(this);
    }
    const pipeline = new Pipeline(this);
    // @ts-expect-error
    pipeline.multi();
    if (Array.isArray(commands)) {
      pipeline.addBatch(commands);
    }
    const exec = pipeline.exec;
    pipeline.exec = function (callback: Callback) {
      // Wait for the cluster to be connected, since we need nodes information before continuing
      if (this.isCluster && !this.redis.slots.length) {
        if (this.redis.status === "wait") this.redis.connect().catch(noop);
        return asCallback(
          new Promise((resolve, reject) => {
            this.redis.delayUntilReady((err) => {
              if (err) {
                reject(err);
                return;
              }

              this.exec(pipeline).then(resolve, reject);
            });
          }),
          callback
        );
      }

      if (this._transactions > 0) {
        exec.call(pipeline);
      }

      // Returns directly when the pipeline
      // has been called multiple times (retries).
      if (this.nodeifiedPromise) {
        return exec.call(pipeline);
      }
      const promise = exec.call(pipeline);
      return asCallback(
        promise.then(function (result: any[]): any[] | null {
          const execResult = result[result.length - 1];
          if (typeof execResult === "undefined") {
            throw new Error(
              "Pipeline cannot be used to send any commands when the `exec()` has been called on it."
            );
          }
          if (execResult[0]) {
            execResult[0].previousErrors = [];
            for (let i = 0; i < result.length - 1; ++i) {
              if (result[i][0]) {
                execResult[0].previousErrors.push(result[i][0]);
              }
            }
            throw execResult[0];
          }
          return wrapMultiResult(execResult[1]);
        }),
        callback
      );
    };

    // @ts-expect-error
    const { execBuffer } = pipeline;
    // @ts-expect-error
    pipeline.execBuffer = function (callback: Callback) {
      if (this._transactions > 0) {
        execBuffer.call(pipeline);
      }
      return pipeline.exec(callback);
    };
    return pipeline;
  };

  const { exec } = redis;
  redis.exec = function (callback: Callback): Promise<any[] | null> {
    return asCallback(
      exec.call(this).then(function (results: any[] | null) {
        if (Array.isArray(results)) {
          results = wrapMultiResult(results);
        }
        return results;
      }),
      callback
    );
  };
}