javascript knexfile can't run typescript migrations

Environment

Knex version: 0.21.1 Database + version: postgres 12 OS: Linux

Bug

1. Description

When the knexfile has js extension, typescript migrations and seeds can’t be run. The error thrown suggests these files are not loaded with typescript loader. Changing knexfile extension to ts fixes the problem.

This is rather unexpected, as the documentation suggests that knex can run migrations of different types, no matter what the knexfile extension is.

loadExtensions: array of file extensions which knex will treat as migrations.

1. Error message

import Knex from 'knex';
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at wrapSafe (internal/modules/cjs/loader.js:1047:16)
    at Module._compile (internal/modules/cjs/loader.js:1097:27)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1153:10)
    at Module.load (internal/modules/cjs/loader.js:977:32)
    at Function.Module._load (internal/modules/cjs/loader.js:877:14)
    at Module.require (internal/modules/cjs/loader.js:1019:19)
    at require (internal/modules/cjs/helpers.js:77:18)
    at FsMigrations.getMigration (/home/przemek/DEV/sundae/sundae-collab-demo-api/node_modules/knex/lib/migrate/sources/fs-migrations.js:82:12)
    at /home/przemek/DEV/sundae/sundae-collab-demo-api/node_modules/knex/lib/migrate/Migrator.js:76:67
    at Array.some (<anonymous>)

1. Knexfile content

require('dotenv').config();

const defaultSettings = {
  // client
  // connection
};

module.exports.development = {
  ...defaultSettings,
  migrations: {
    loadExtensions: ['.ts'],
    extension: 'ts',
  },
  seeds: {
    loadExtensions: ['.ts'],
  },
};

module.exports.test = {
  ...defaultSettings,
  migrations: {
    loadExtensions: ['.ts'],
    extension: 'ts',
  },
  seeds: {
    loadExtensions: ['.ts'],
  },
};

module.exports.production = {
  ...defaultSettings,
  migrations: {
    directory: 'build/migrations',
  },
  seeds: {
    directory: 'build/seeds',
  },
};

Feature discussion / request

1. Explain what is your use case

I want to run Typescript migrations and seeds in development environment. In production, where Typescript and ts-node might not be present, compiled migrations and seeds should be used instead. Ideally, one js knexfile would handle both cases.

1. Explain what kind of feature would support this

Knexfile extension should not influence migration and seed loading. When loadExtensions includes .ts, typescript migrations and seeds should be loaded and run.

[Adverbly]

For those seeing

Failed to load external module ts-node/register
Failed to load external module typescript-node/register
Failed to load external module typescript-register
Failed to load external module typescript-require
Failed to load external module sucrase/register/ts
Failed to load external module @babel/register
Error: Cannot find module 'ts-node/register'
...
SyntaxError: Cannot use import statement outside a module

for me the fix was that I was missing ts-node from my package.json. A simple

npm install -D ts-node

was all I needed.

[lorefnon]

@abcd-ca You can use:

TS_NODE_COMPILER_OPTIONS='{ "module": "commonjs" }' knex migrate:latest

knex uses ts-node’s require hook for .ts extension and that can accept TS compiler options through TS_NODE_COMPILER_OPTIONS env variable. These options will be merged into what you have in your tsconfig.json.