Output warning when using bad npm version

src/npm.ts

@@ -1,17 +1,41 @@
 import * as path from 'path';
 import * as cp from 'child_process';
 
-const cmd = 'npm list --production --parseable';
+const listCmd = 'npm list --production --parseable';
 
 export function getDependencies(cwd: string): Promise<string[]> {
-	return new Promise<string[]>((c, e) => {
-		cp.exec(cmd, { cwd }, (err, stdout, stderr) => {
-				if (err) return e(err);
-
-				c(stdout.toString('utf8')
-					.split(/[\r\n]/)
-					.filter(dir => path.isAbsolute(dir)));
+	return isBadNpmVersion()
+		.then((isBadVersion) => {
+			if(isBadVersion) {
+				console.warn('You are using a npm version, that does not work well with vsce! Consider to update with "npm install -g npm".')
 			}
-		);
+		}).then(() => {
+			return new Promise<string[]>((c, e) => {
+				cp.exec(listCmd, { cwd }, (err, stdout, stderr) => {
+						if (err) return e(err);
+
+						c(stdout.toString('utf8')
+							.split(/[\r\n]/)
+							.filter(dir => path.isAbsolute(dir)));
+					}
+				);
+			});
+		});
+}
+
+const versionCmd = 'npm -v';
+
+const badNpmVersions = [
+	/3.7.[0123]/
+];
+
+export function isBadNpmVersion(): Promise<boolean> {
+	return new Promise<boolean>((c, e) => {
+		cp.exec(versionCmd, (err, stdout, stderr) => {
+			if (err) return e(err);
+
+			let version = stdout.toString('utf8').trim();
+			c(badNpmVersions.some((regex) => regex.test(version)));
+		});
 	});
 }