Question: using typescript template in an nx monorepo

[DaveLo]

I think this is somewhat related to #28 ,

I'm getting initialization errors when I try to run serverless commands in the nx app directory. This happens whether I cd into the the directory and run manually or use nx run commands.

What I've noticed is if I point serverless webpack at tsconfig.app.json, but there is a tsconfig.json file in the same directory I get an initialization error. If I rename the tsconfig file to something else then the serverless.ts file will initialize and run serverless commands, but I lose my paths info from the monorepo context.

I feel like there is probably a setting (or there should be) to tell serverless to use exactly this tsconfig file only and ignore others?

code

tsconfig files

/* tsconfig.app.json */
{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "target": "ES2020",
    "types": ["node"],
    "lib": ["esnext"],
    "skipLibCheck": true
  },
  "exclude": [
    "**/*.spec.ts",
    "node_modules/**/*",
    ".serverless/**/*",
    ".webpack/**/*",
    "_warmup/**/*",
    ".vscode/**/*"
  ],
  "include": ["src/**/*.ts", "serverless.ts"],
  "ts-node": {
    "require": ["tsconfig-paths/register"]
  }
}

/* tsconfig.json */
{
  "extends": "../../../tsconfig.base.json",
  "files": [],
  "include": [],
  "references": [
    {
      "path": "./tsconfig.app.json"
    },
    {
      "path": "./tsconfig.spec.json"
    }
  ]
}

/* tsconfig.base.json */
{
  "compileOnSave": false,
  "compilerOptions": {
    "rootDir": ".",
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "importHelpers": true,
    "target": "esnext",
    "module": "esnext",
    "lib": ["esnext", "dom"],
    "skipLibCheck": true,
    "skipDefaultLibCheck": true,
    "baseUrl": ".",
    "paths": {/* lots of paths */}
  },
  "exclude": ["node_modules", "tmp"]
}

serverless file

/** serverless.ts */
import type * as sls from "@serverless/typescript";

import hello from "./src/hello";

const slsWebpackConfig = {
  webpackConfig: "./webpack.config.js",
  includeModules: {
    forceExclude: ["aws-sdk"],
  },
};

const prunePluginConfig = {
  automatic: true,
  number: 3,
};

const serverlessConfiguration: sls.AWS = {
  service: "cloud-api",
  org: "southtreebot",
  app: "cloud-backup",
  frameworkVersion: "2",
  custom: {
    stage: '${opt:stage, "Dev"}',
    webpack: slsWebpackConfig,
    prune: prunePluginConfig,
  },
  /** removed some deployment bucket info */
  plugins: ["serverless-prune-plugin", "serverless-webpack"],
  provider: {
    name: "aws",
    runtime: "nodejs14.x",
    region: "us-east-1",
    logRetentionInDays: 731,
    apiGateway: {
      minimumCompressionSize: 1024,
      shouldStartNameWithService: true,
    },
    lambdaHashingVersion: "20201221",
    iam: {
      role: {
        managedPolicies: [
          {
            "Fn::Sub":
              "arn:aws:iam::${AWS::AccountId}:policy/PutEventBridgeEventsPolicy",
          },
        ],
      },
    },
    environment: {
      AWS_NODEJS_CONNECTION_REUSE_ENABLED: "1",
      ENV_STAGE: "${self:custom.stage}",
    },
  },
  package: {
    individually: true,
    exclude: ["*.json", "*.md"],
  },
  functions: {
    hello,
  },
  // resources: {},
};

module.exports = serverlessConfiguration;

error text

Cannot load "serverless.ts": Initialization error: /Users/**/**/apps/cloud/api/serverless.ts:59
  export {};
  ^^^^^^
  
  SyntaxError: Unexpected token 'export'
      at wrapSafe (internal/modules/cjs/loader.js:979:16)
      at Module._compile (internal/modules/cjs/loader.js:1027:27)
      at Module.m._compile (/Users/**/**/node_modules/ts-node/src/index.ts:1056:23)
      at Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
      at Object.require.extensions.<computed> [as .ts] (/Users/**/**/node_modules/ts-node/src/index.ts:1059:12)
      at Module.load (internal/modules/cjs/loader.js:928:32)
      at Function.Module._load (internal/modules/cjs/loader.js:769:14)
      at Module.require (internal/modules/cjs/loader.js:952:19)
      at require (internal/modules/cjs/helpers.js:88:18)
      at /Users/**/.nvm/versions/node/v14.15.0/lib/node_modules/serverless/lib/configuration/read.js:121:18
      at parseConfigurationFile (/Users/**/.nvm/versions/node/v14.15.0/lib/node_modules/serverless/lib/configuration/read.js:136:9)
      at processTicksAndRejections (internal/process/task_queues.js:93:5)
      at module.exports (/Users/**/.nvm/versions/node/v14.15.0/lib/node_modules/serverless/lib/configuration/read.js:163:23)
      at /Users/**/.nvm/versions/node/v14.15.0/lib/node_modules/serverless/scripts/serverless.js:112:22
      at /Users/**/.nvm/versions/node/v14.15.0/lib/node_modules/serverless/scripts/serverless.js:110:11

interestingly it is compiling, because line 59 of the ts file is not the export statement.

If I run a tsc in the directory it compiles to js and adds an export {} on line 59; however, if I add the --project flag with tsconfig.app.json it compiles correctly and serverless will run that compiled js file with no issue.

env

Your Environment Information ---------------------------
     Operating System:          darwin
     Node Version:              14.15.0
     Framework Version:         2.34.0
     Plugin Version:            4.5.3
     SDK Version:               4.2.2
     Components Version:        3.8.2

[fredericbarthelet]

Hi @DaveLo and thanks for reporting your issue.

I feel like there is probably a setting (or there should be) to tell serverless to use exactly this tsconfig file only and ignore others?

Indeed, the result from #28 shows that using env variable TS_NODE_CONFIG=./tsconfig.app.json does the trick of letting serverless know which file you'd like to use -> https://github.com/serverless/serverless/tree/master/lib/plugins/create/templates/aws-nodejs-typescript#advanced-usage

Is this solution compatible with your monorepo usage (you'd have to specify a dedicated env variable for each module I believe) ?

[DaveLo]

I did try that, but it seems to still latch onto there being a tsconfig.json in the directory?

I thought it was interesting that running the same command (with the env var) would fail with a tsconfig.json in the lib and succeed if I changed that to tsconfig.lib.json. If that didn't break typescript references inside the directory it would be workable , but sadly it seems to (probably something with how Nx works behind the scenes?).

To get unblocked I've switched the app to using a yaml file and that seems to mostly work (although sad because I love the way the ts template is structured and having type hints).

[fredericbarthelet]

Hi @DaveLo, if you want to get involved in this, we're currently reworking the way serverless framework loads service file defined in TS in this issue serverless/serverless#9311
In the meantime, I'm closing this. Thanks for your feedbacks :)!