Make extension config override instead of deep merge

Fixes dividab#94

package.json

@@ -9,7 +9,6 @@
   "repository": "https://github.com/dividab/tsconfig-paths",
   "devDependencies": {
     "@types/chai": "^4.1.4",
-    "@types/deepmerge": "^1.3.2",
     "@types/minimist": "^1.2.0",
     "@types/mocha": "^5.2.3",
     "@types/node": "^6.0.54",
@@ -30,7 +29,6 @@
   },
   "dependencies": {
     "@types/json5": "^0.0.29",
-    "deepmerge": "^2.0.1",
     "json5": "^1.0.1",
     "minimist": "^1.2.0",
     "strip-bom": "^3.0.0"

src/tsconfig-loader.ts

@@ -1,6 +1,5 @@
 import * as path from "path";
 import * as fs from "fs";
-import * as deepmerge from "deepmerge";
 // tslint:disable:no-require-imports
 import JSON5 = require("json5");
 import StripBom = require("strip-bom");
@@ -14,6 +13,7 @@ export interface Tsconfig {
   compilerOptions?: {
     baseUrl?: string;
     paths?: { [key: string]: Array<string> };
+    strict?: boolean;
   };
 }
 
@@ -139,7 +139,14 @@ export function loadTsconfig(
       );
     }
 
-    return deepmerge(base, config);
+    return {
+      ...base,
+      ...config,
+      compilerOptions: {
+        ...base.compilerOptions,
+        ...config.compilerOptions
+      }
+    };
   }
   return config;
 }

test/tsconfig-loader-tests.ts

@@ -130,14 +130,18 @@ describe("loadConfig", () => {
     assert.deepEqual(res, config);
   });
 
-  it("It should load a config with extends and overwrite baseUrl", () => {
+  it("It should load a config with extends and overwrite all options", () => {
     const firstConfig = {
       extends: "../base-config.json",
-      compilerOptions: { baseUrl: "kalle" }
+      compilerOptions: { baseUrl: "kalle", paths: { foo: ["bar2"] } }
     };
     const firstConfigPath = join("/root", "dir1", "tsconfig.json");
     const baseConfig = {
-      compilerOptions: { baseUrl: "olle", paths: { foo: ["bar"] } }
+      compilerOptions: {
+        baseUrl: "olle",
+        paths: { foo: ["bar1"] },
+        strict: true
+      }
     };
     const baseConfigPath = join("/root", "base-config.json");
     const res = loadTsconfig(
@@ -156,7 +160,11 @@ describe("loadConfig", () => {
 
     assert.deepEqual(res, {
       extends: "../base-config.json",
-      compilerOptions: { baseUrl: "kalle", paths: { foo: ["bar"] } }
+      compilerOptions: {
+        baseUrl: "kalle",
+        paths: { foo: ["bar2"] },
+        strict: true
+      }
     });
   });
 

yarn.lock

@@ -6,10 +6,6 @@
   version "4.1.4"
   resolved "https://registry.yarnpkg.com/@types/chai/-/chai-4.1.4.tgz#5ca073b330d90b4066d6ce18f60d57f2084ce8ca"
 
-"@types/deepmerge@^1.3.2":
-  version "1.3.2"
-  resolved "https://registry.yarnpkg.com/@types/deepmerge/-/deepmerge-1.3.2.tgz#a87837384624d63e8c3df3ae85693d574ea6b5db"
-
 "@types/json5@^0.0.29":
   version "0.0.29"
   resolved "https://registry.yarnpkg.com/@types/json5/-/json5-0.0.29.tgz#ee28707ae94e11d2b827bcbe5270bcea7f3e71ee"
@@ -485,10 +481,6 @@ deep-eql@^3.0.0:
   dependencies:
     type-detect "^4.0.0"
 
-deepmerge@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/deepmerge/-/deepmerge-2.0.1.tgz#25c1c24f110fb914f80001b925264dd77f3f4312"
-
 default-require-extensions@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/default-require-extensions/-/default-require-extensions-1.0.0.tgz#f37ea15d3e13ffd9b437d33e1a75b5fb97874cb8"