Module aliases are not interpreted

[serverless]

Module aliases are not interpreted

[mr-piratman]

this is working for me
https://www.npmjs.com/package/serverless-tscpaths

just
$ yarn add serverless-tscpaths -D

and in your serverless.yml

plugins:
  - serverless-plugin-typescript
  - serverless-tscpaths # should be after serverless-plugin-typescript

[brothatru]

If you are using serverless-webpack (installed by default if you used sls create --template aws-nodejs-typescript)

In your webpack.config.js

// webpack.config.js
resolve: {
  extensions: ['.ts'],
  alias: {
    '@app': path.resolve(__dirname, './src'),
  },
},

// tsconfig.json
"baseUrl": "./src/",
"paths": {
    "@app/*": ["./*"]
},

Found in this thread

[trungtin]

As I can see from that issue, this will be non-fixed from typescript team.

One alternative is using something like https://github.com/ilearnio/module-alias/, but because of each function is compiled separately so is there a way to prepend the register code require('module-alias/register') before every function?

[kaveet]

I spent a bit of time looking into this, and here are the options as I see them:

1. Use relative imports

2. Switch to a bundler like Webpack with known support for module aliases and their resolution (e.g. serverless-webpack)

3. Use something like module-alias in your functions to resolve these paths at runtime

   Workable, but you face issues like duplicating the aliases across two configs and remembering to register the modules in every file

4. Rewrite aliased paths to relative ones in the emitted code

   There are several projects doing this for TypeScript, but many are outdated: tspath

I took a stab at implementing 3 and 4 as complementary Serverless plugins to this one (they feel out-of-scope for this plugin). I do think this is possible to solve for via plugins that rewrite the emitted code, but decided I'd personally rather use Webpack for the sake of time and stability. If anyone wants to pick up where I left off, here's what I learned:

• Number 3 is certainly easier to implement, but comes with its own set of pitfalls (https://github.com/ilearnio/module-alias/#known-incompatibilities)
• Hook into the same Serverless lifecycle events as this plugin does, but register your plugin after this one. You might have to do some juggling with the build paths to write out the modified code correctly
• Read tsconfig.json into your plugin to eliminate duplicate configuration of aliases, especially if using something like module-alias

[jonnyasmar]

So, I solved this problem in a pretty trivial manner...

I got rid of serverless-plugin-typescript and created a bundle of my TS using Webpack. The resulting JS bundle is then deployed via sls deploy.

Simple solution, but doesn't leverage this plugin at all.

[pie6k]

I have the same issue

[leejh3224]

I found out that baseUrl option in tsconfig.json also doesn't work.

So I replaced all the import statement with relative syntax :(

[manuabhijit]

So, I solved this problem in a pretty trivial manner...

I got rid of serverless-plugin-typescript and created a bundle of my TS using Webpack. The resulting JS bundle is then deployed via sls deploy.

Simple solution, but doesn't leverage this plugin at all.

Please be more detailed. I am facing the same issue.

[JackCuthbert]

My understanding is that this issue is related to TypeScript and not this plugin. Typescript does indeed support module path aliases during compilation, but will not emit these aliased paths, see microsoft/TypeScript#10866.

Please feel free to re-open a new issue if you think it's still relevant 😄

[ericmaicon]

@trungtin have you found a solution?

[trungtin]

@ericmaicon nope, I switch to serverless-webpack for the moment.

[joshdura]

Has anyone found a solution to this?

[joaodfmota]

I'm using aliases with
https://github.com/AnomalyInnovations/serverless-bundle

[karltaylor]

I'm using aliases with
https://github.com/AnomalyInnovations/serverless-bundle

Can you elaborate @joaodfmota? I'm trying to find a simple solution, I've added the following to serverless.yml to no success

custom:
  bundle:
    stats: false
    aliases:
      - src: "./"