From 1a8d3f01ef67f6ce2bbecf552bc09fca5b0b8250 Mon Sep 17 00:00:00 2001
From: achingbrain <alex@achingbrain.net>
Date: Tue, 23 Nov 2021 11:28:09 +0000
Subject: [PATCH] fix: add .js extension to imports and fix package.json

This fixes two problems with the ESM build of this module.

1. The `package.json` that contains `{ "type": "module" }` wasn't being included in the npm tarball
2. When running in an ESM environment, `import foo from './bar'` does not work, you have to specify the extension

The fix for the first is simple, add the cjs/esm `package.json` files to the `files`
array in the project `package.json`.

The second fix is harder.  If you just add the `.js` extension to the source files,
typescript is happy but ts-node is not, and this project uses ts-node to run the
tests without a compile step.

Typescript does not support importing `*.ts` and will not support adding `*.js` to
the transpiled output - https://github.com/microsoft/TypeScript/issues/16577

ts-node thought this was a bug in Typescript but it turns out not.  Their suggestion
to use `ts-node/esm` breaks sourcemap support because `source-map-support/register`
is not esm - https://github.com/TypeStrong/ts-node/issues/783

There is a PR against ts-node to add support for resolving `./foo.js` if `./foo.ts`
or `./foo` fails but it seems to have stalled - https://github.com/TypeStrong/ts-node/pull/1361

Given all of the above, the most expedient way forward seemed to just be to add
a shell script that rewrites the various `import` statements in the esm output
to add the `.js` extension, then if the ts-node PR ever gets merged the script
can be backed out.

Fixes #147
---
 .fix-esm-imports.sh | 4 ++++
 package.json        | 5 +++--
 2 files changed, 7 insertions(+), 2 deletions(-)
 create mode 100755 .fix-esm-imports.sh

diff --git a/.fix-esm-imports.sh b/.fix-esm-imports.sh
new file mode 100755
index 0000000..7e4df1e
--- /dev/null
+++ b/.fix-esm-imports.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+# Search for "from './baz'" and transform to "from './baz.js'"
+find dist/esm -type f -name *.js -exec sed -i -e -E "s/from '(\.\/.*)'/from '\1.js'/g" {} \;
\ No newline at end of file
diff --git a/package.json b/package.json
index 1534c2e..57ba940 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
   },
   "scripts": {
     "docs": "documentation build --github --output docs --format html ./ip-address.js",
-    "build": "rm -rf dist/* && tsc -p tsconfig.json && tsc -p tsconfig-esm.json && ./.fix-package-types.sh",
+    "build": "rm -rf dist/* && tsc -p tsconfig.json && tsc -p tsconfig-esm.json && ./.fix-package-types.sh && ./.fix-esm-imports.sh",
     "prepublishOnly": "npm run build",
     "release": "release-it",
     "test-ci": "nyc mocha",
@@ -53,7 +53,8 @@
   "files": [
     "dist/**/*.js",
     "dist/**/*.ts",
-    "dist/**/*.map"
+    "dist/**/*.map",
+    "dist/**/*.json"
   ],
   "repository": {
     "type": "git",