Automatically install missing dependencies, part 2

package.json

@@ -37,6 +37,7 @@
     "mkdirp": "^0.5.1",
     "node-forge": "^0.7.1",
     "node-libs-browser": "^2.0.0",
+    "npm-programmatic": "^0.0.10",
     "opn": "^5.1.0",
     "physical-cpu-count": "^2.0.0",
     "postcss": "^6.0.10",

src/Bundler.js

@@ -16,6 +16,7 @@ const config = require('./utils/config');
 const emoji = require('./utils/emoji');
 const loadEnv = require('./utils/env');
 const PromiseQueue = require('./utils/PromiseQueue');
+const npm = require('npm-programmatic');
 
 /**
  * The Bundler is the main entry point. It resolves and loads assets,
@@ -328,26 +329,43 @@ class Bundler extends EventEmitter {
       let thrown = err;
 
       if (thrown.message.indexOf(`Cannot find module '${dep.name}'`) === 0) {
-        if (dep.optional) {
-          return;
-        }
-
-        thrown.message = `Cannot resolve dependency '${dep.name}'`;
-
-        // Add absolute path to the error message if the dependency specifies a relative path
-        if (dep.name.startsWith('.')) {
-          const absPath = Path.resolve(Path.dirname(asset.name), dep.name);
-          err.message += ` at '${absPath}'`;
-        }
-
-        // Generate a code frame where the dependency was used
-        if (dep.loc) {
-          await asset.loadIfNeeded();
-          thrown.loc = dep.loc;
-          thrown = asset.generateErrorMessage(thrown);
+        let isLocalFile = dep.name.startsWith('.');
+
+        if (!isLocalFile) {
+          try {
+            try {
+              logger.status(emoji.progress, `Installing ${dep.name}...`);
+              await npm.install([dep.name], {
+                cwd: Path.dirname(asset.name)
+              });
+            } catch (npmError) {
+              logger.error(npmError.message);
+            }
+
+            return await this.resolveAsset(dep.name, asset.name);
+          } catch (e) {
+            if (dep.optional) {
+              return;
+            }
+
+            thrown.message = `Cannot resolve dependency '${dep.name}'`;
+
+            // Add absolute path to the error message if the dependency specifies a relative path
+            if (isLocalFile) {
+              const absPath = Path.resolve(Path.dirname(asset.name), dep.name);
+              err.message += ` at '${absPath}'`;
+            }
+
+            // Generate a code frame where the dependency was used
+            if (dep.loc) {
+              await asset.loadIfNeeded();
+              thrown.loc = dep.loc;
+              thrown = asset.generateErrorMessage(thrown);
+            }
+
+            thrown.fileName = asset.name;
+          }
         }
-
-        thrown.fileName = asset.name;
       }
       throw thrown;
     }

yarn.lock

@@ -825,7 +825,7 @@ block-stream@*:
   dependencies:
     inherits "~2.0.0"
 
-bluebird@^3.0.5:
+bluebird@^3.0.5, bluebird@^3.4.1:
   version "3.5.1"
   resolved "https://npm.cubos.io/bluebird/-/bluebird-3.5.1.tgz#d9551f9de98f1fcda1e683d17ee91a0602ee2eb9"
 
@@ -4015,6 +4015,12 @@ npm-path@^2.0.2:
   dependencies:
     which "^1.2.10"
 
+npm-programmatic@^0.0.10:
+  version "0.0.10"
+  resolved "https://registry.yarnpkg.com/npm-programmatic/-/npm-programmatic-0.0.10.tgz#9765820505d03083e57c6a7729bed515997a61c9"
+  dependencies:
+    bluebird "^3.4.1"
+
 npm-run-path@^2.0.0:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/npm-run-path/-/npm-run-path-2.0.2.tgz#35a9232dfa35d7067b4cb2ddf2357b1871536c5f"