From 835bab170a80d47616595c31a9d9b92e46acde6f Mon Sep 17 00:00:00 2001
From: Farzan <farzan.doroodgar@gmail.com>
Date: Sat, 20 Nov 2021 13:50:27 +0330
Subject: [PATCH] Add support for baseUrl override using TS_NODE_BASEURL env
 var (#185)

---
 README.md                     |  4 +++
 src/tsconfig-loader.ts        | 20 +++++++++++---
 test/tsconfig-loader-tests.ts | 49 ++++++++++++++++++++++++++++++-----
 3 files changed, 62 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index 35369cb..0ccab34 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,10 @@ npm install --save-dev tsconfig-paths
 
 `node -r tsconfig-paths/register main.js`
 
+If `process.env.TS_NODE_BASEURL` is set it will override the value of `baseUrl` in tsconfig.json:
+
+`TS_NODE_BASEURL=./dist node -r tsconfig-paths/register main.js`
+
 ### With ts-node
 
 `ts-node -r tsconfig-paths/register main.ts`
diff --git a/src/tsconfig-loader.ts b/src/tsconfig-loader.ts
index 8ccdcff..c2dfb04 100644
--- a/src/tsconfig-loader.ts
+++ b/src/tsconfig-loader.ts
@@ -26,7 +26,11 @@ export interface TsConfigLoaderResult {
 export interface TsConfigLoaderParams {
   getEnv: (key: string) => string | undefined;
   cwd: string;
-  loadSync?(cwd: string, filename?: string): TsConfigLoaderResult;
+  loadSync?(
+    cwd: string,
+    filename?: string,
+    baseUrl?: string
+  ): TsConfigLoaderResult;
 }
 
 export function tsConfigLoader({
@@ -35,13 +39,19 @@ export function tsConfigLoader({
   loadSync = loadSyncDefault,
 }: TsConfigLoaderParams): TsConfigLoaderResult {
   const TS_NODE_PROJECT = getEnv("TS_NODE_PROJECT");
+  const TS_NODE_BASEURL = getEnv("TS_NODE_BASEURL");
 
   // tsconfig.loadSync handles if TS_NODE_PROJECT is a file or directory
-  const loadResult = loadSync(cwd, TS_NODE_PROJECT);
+  // and also overrides baseURL if TS_NODE_BASEURL is available.
+  const loadResult = loadSync(cwd, TS_NODE_PROJECT, TS_NODE_BASEURL);
   return loadResult;
 }
 
-function loadSyncDefault(cwd: string, filename?: string): TsConfigLoaderResult {
+function loadSyncDefault(
+  cwd: string,
+  filename?: string,
+  baseUrl?: string
+): TsConfigLoaderResult {
   // Tsconfig.loadSync uses path.resolve. This is why we can use an absolute path as filename
 
   const configPath = resolveConfigPath(cwd, filename);
@@ -57,7 +67,9 @@ function loadSyncDefault(cwd: string, filename?: string): TsConfigLoaderResult {
 
   return {
     tsConfigPath: configPath,
-    baseUrl: config && config.compilerOptions && config.compilerOptions.baseUrl,
+    baseUrl:
+      baseUrl ||
+      (config && config.compilerOptions && config.compilerOptions.baseUrl),
     paths: config && config.compilerOptions && config.compilerOptions.paths,
   };
 }
diff --git a/test/tsconfig-loader-tests.ts b/test/tsconfig-loader-tests.ts
index 9849d96..37d5494 100644
--- a/test/tsconfig-loader-tests.ts
+++ b/test/tsconfig-loader-tests.ts
@@ -63,6 +63,41 @@ describe("tsconfig-loader", () => {
 
     assert.equal(result.tsConfigPath, "/foo/baz/tsconfig.json");
   });
+
+  it("should use TS_NODE_BASEURL env if exists", () => {
+    const result = tsConfigLoader({
+      cwd: "/foo/bar",
+      getEnv: (key: string) =>
+        key === "TS_NODE_BASEURL" ? "SOME_BASEURL" : undefined,
+      loadSync: (_0: string, _1: string, baseUrl: string) => {
+        return {
+          tsConfigPath: undefined,
+          baseUrl,
+          paths: {},
+        };
+      },
+    });
+
+    assert.equal(result.baseUrl, "SOME_BASEURL");
+  });
+
+  it("should not use TS_NODE_BASEURL env if it does not exist", () => {
+    const result = tsConfigLoader({
+      cwd: "/foo/bar",
+      getEnv: (_: string) => {
+        return undefined;
+      },
+      loadSync: (_0: string, _1: string, baseUrl: string) => {
+        return {
+          tsConfigPath: undefined,
+          baseUrl,
+          paths: {},
+        };
+      },
+    });
+
+    assert.equal(result.baseUrl, undefined);
+  });
 });
 
 describe("walkForTsConfig", () => {
@@ -171,15 +206,15 @@ describe("loadConfig", () => {
   it("It should load a config with extends from node_modules and overwrite all options", () => {
     const firstConfig = {
       extends: "my-package/base-config.json",
-      compilerOptions: { baseUrl: "kalle", paths: { foo: ["bar2"] } }
+      compilerOptions: { baseUrl: "kalle", paths: { foo: ["bar2"] } },
     };
     const firstConfigPath = join("/root", "dir1", "tsconfig.json");
     const baseConfig = {
       compilerOptions: {
         baseUrl: "olle",
         paths: { foo: ["bar1"] },
-        strict: true
-      }
+        strict: true,
+      },
     };
     const baseConfigPath = join(
       "/root",
@@ -190,8 +225,8 @@ describe("loadConfig", () => {
     );
     const res = loadTsconfig(
       join("/root", "dir1", "tsconfig.json"),
-      path => path === firstConfigPath || path === baseConfigPath,
-      path => {
+      (path) => path === firstConfigPath || path === baseConfigPath,
+      (path) => {
         if (path === firstConfigPath) {
           return JSON.stringify(firstConfig);
         }
@@ -207,8 +242,8 @@ describe("loadConfig", () => {
       compilerOptions: {
         baseUrl: "kalle",
         paths: { foo: ["bar2"] },
-        strict: true
-      }
+        strict: true,
+      },
     });
   });