esbuild + knex: Cannot find module '../../dialects/mysql/index.js'

Issue

I'm currently trying to migrate some code from javascript to typescript. This code uses the knex package. I am able to build and run it using tsc, but i would like to use esbuild instead (for faster build).

I build with:

npx esbuild index.ts --bundle --platform=node --sourcemap=external --outfile=dist/index.js

But when i try to run the compiled code, i get:

Cannot find module '../../dialects/mysql/index.js'

I have no idea what is this dialect directory, and couldn't find any documentatio about it. I took a look at this SO question, but couldn't really understand the code in it, and the error seemed to be more about browserified.

Here is the code I used to reproduce the error:

import Knex from 'knex';

const knex = Knex({
  client: 'mysql',
  connection: {
    port: 3306,
    host: 'localhost',
    database: 'database',
    user: 'user',
    password: 'password',
    charset: 'utf8mb4',
  },
});

const fetchData = async () => {
  const data = await knex('table')
    .select()
    .first();
  return data;
};

(async () => {
  const results = await fetchData();
  console.log(results);
})();

Interesting thing is that by using only the mysql package without knex worked great with both tsc and esbuild.

For some reason only the build from esbuild fails. I first thought i missed a package, and i installed @types/node and @types/mysql but it didn't solved my problem.

If it helps, i use the following tsconfig.json:

{
  "compilerOptions": {
    "module": "commonjs",
    "moduleResolution": "node",
    "outDir": "dist",
    "target": "es6",
    "esModuleInterop": true
  }
}

Solution

This is a problem I've had as well and I came across a related thread on the esbuild GitHub.

You'll just need to update your knex initialisation to the following:

import Knex from 'knex';
import KnexMysql from 'knex/lib/dialects/mysql';

const knex = Knex({
  client: KnexMysql,
  ...
});

Answered By - j-petty