Support for Command.setArgumentTransformer

[haakonnessjoen]

We are using this handy piece of code, to be able to work with hashes as objects in js:

function convertMapToArray(map: any): any[] {
	const result: any[] = []
	let pos = 0
	map.forEach(function (value: any, key: any) {
		result[pos] = key
		result[pos + 1] = value
		pos += 2
	})
	return result
}

function convertObjectToArray(obj: any): any[] {
	var result: any[] = []
	var keys = Object.keys(obj)

	for (var i = 0, l = keys.length; i < l; i++) {
		result.push(keys[i], obj[keys[i]])
	}
	return result
}

Redis.Command.setArgumentTransformer('hmset', function (args) {
	if (args.length === 2) {
		if (typeof Map !== 'undefined' && args[1] instanceof Map) {
			// utils is a internal module of ioredis
			return [args[0]].concat(convertMapToArray(args[1]))
		}
		if (typeof args[1] === 'object' && args[1] !== null) {
			return [args[0]].concat(convertObjectToArray(args[1]))
		}
	}
	return args
})

Redis.Command.setReplyTransformer('hgetall', function (result) {
	if (Array.isArray(result)) {
		const obj: any = {}
		for (var i = 0; i < result.length; i += 2) {
			obj[result[i]] = result[i + 1]
		}
		return obj
	}
	return result
})

But when using ioredis-mock, i get the following error:

TypeError: Cannot read property 'setArgumentTransformer' of undefined

      23 | }
      24 |
    > 25 | Redis.Command.setArgumentTransformer('hmset', function (args) {
         |               ^
      26 |      if (args.length === 2) {
      27 |              if (typeof Map !== 'undefined' && args[1] instanceof Map) {
      28 |                      // utils is a internal module of ioredis

      at Object.<anonymous> (src/lib/redis.ts:25:15)

So I guess that is not supported, as it works without ioredis-mock. It would be awesome to get support for that though.

[haakonnessjoen]

Ok. So I see now that you are supposed to support it.
So the way I am using it now is with jest and this code:

const ioredisMock = require('ioredis-mock')
jest.setMock('ioredis', ioredisMock)

In the other module using ioredis, I tried console.log("Redis:", Redis) and console.log("Redis.Command:", Redis.Command), and got the following when it is being mocked:

Redis: [class RedisMock extends EventEmitter]
Redis.Command: undefined

And I am using ioredis-mock@5.2.4

[stipsan]

Yeah the thing is that it's tricky to make jest module mocking work when the mock is importing something from the original.

There's more alternative approaches in this thread: #568

It sounds like this approach is the most likely to succeed, but perhaps cost the most to implement, depending on how many import calls in your codebase that'll need to be updated: #568 (comment)

Perhaps the best solution here is if we added another import you could use, specifically for jest:

const ioredisMock = require('ioredis-mock/jest')
jest.setMock('ioredis', ioredisMock)

In the ioredis-mock/jest.js file we could simply inline import { Command } from 'ioredis'; to ensure that the jest module mocking system no longer have to deal with the circular dependency.

[stipsan]

@haakonnessjoen starting with v5.4 you can use this approach:

jest.mock('ioredis', () => require('ioredis-mock/jest'));

[haakonnessjoen]

I am still having the same issue:
TypeError: Cannot read property 'setArgumentTransformer' of undefined

Is it simply that ioredis-mock do not work with typescript at all, since ioredis is imported in the main code?

[stipsan]

I am still having the same issue:

TypeError: Cannot read property 'setArgumentTransformer' of undefined

Is it simply that ioredis-mock do not work with typescript at all, since ioredis is imported in the main code?

Is that with the new ioredis-mock/jest approach? I'll go over the test suite, it should be testing this already 🤔

[silverwind]

Yes, I see it with ioredis-mock/jest. My jest setupFiles has:

jest.mock("ioredis", () => require("ioredis-mock/jest"));

My application uses:

Redis.Command.setReplyTransformer("hgetall", result => {
  const arr = [];
  for (let i = 0; i < result.length; i += 2) {
    arr.push([String(result[i]), String(result[i + 1])]);
  }
  return arr;
});

During the jest run, it throws:

TypeError: Cannot read properties of undefined (reading 'setReplyTransformer')

[silverwind]

I think the issue is that setReplyTransformer and setArgumentTransformer are implemented as RedisMock.prototype.Command, but they should not be on the prototype, but on RedisMock.Command itself as per docs.

> require("ioredis").Command.setReplyTransformer
[Function: setReplyTransformer]

> require("ioredis-mock/jest").Command.setReplyTransformer
Uncaught TypeError: Cannot read properties of undefined (reading 'setReplyTransformer')

[stipsan]

🎉 This issue has been resolved in version 5.8.4 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀