refactor(errors): improve pathFilter error message (#987)

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [next](https://github.com/chimurai/http-proxy-middleware/releases)
 
 - fix(type): fix RequestHandler return type
+- refactor(errors): improve pathFilter error message
 
 ## [v3.0.0](https://github.com/chimurai/http-proxy-middleware/releases/tag/v3.0.0)
 

src/errors.ts

@@ -1,6 +1,6 @@
 export enum ERRORS {
   ERR_CONFIG_FACTORY_TARGET_MISSING = '[HPM] Missing "target" option. Example: {target: "http://www.example.org"}',
-  ERR_CONTEXT_MATCHER_GENERIC = '[HPM] Invalid context. Expecting something like: "/api" or ["/api", "/ajax"]',
-  ERR_CONTEXT_MATCHER_INVALID_ARRAY = '[HPM] Invalid pathFilter. Expecting something like: ["/api", "/ajax"] or ["/api/**", "!**.html"]',
+  ERR_CONTEXT_MATCHER_GENERIC = '[HPM] Invalid pathFilter. Expecting something like: "/api" or ["/api", "/ajax"]',
+  ERR_CONTEXT_MATCHER_INVALID_ARRAY = '[HPM] Invalid pathFilter. Plain paths (e.g. "/api") can not be mixed with globs (e.g. "/api/**"). Expecting something like: ["/api", "/ajax"] or ["/api/**", "!**.html"].',
   ERR_PATH_REWRITER_CONFIG = '[HPM] Invalid pathRewrite config. Expecting object with pathRewrite config or a rewrite function',
 }