extend white/black-listing, update readme

README.md

@@ -10,7 +10,7 @@ Included metrics:
     
 * `up`: normally is just 1
 * `nodejs_memory_heap_total_bytes` and `nodejs_memory_heap_used_bytes`
-* `http_request_total`: count of http requests labeled with status_code
+* `http_request_seconds`: http latency histogram labeled with status_code
 
 ## Install
 
@@ -29,6 +29,7 @@ const
 ## Options
 
  * **prefix**:  prefix added to every metric name
+ * **whitelist**, **blacklist**: array of strings or regexp. These which metrics to include/exclude
 
 ## Example
 
@@ -40,7 +41,8 @@ const express = require("express"),
     promBundle = require("express-prom-bundle");
 
 app.use(promBundle({
-    prefix: "demo_app:something"
+    prefix: "demo_app:something",
+    blacklist: ["up"]
 }));
 
 app.get("/hello", (req, res) => res.send("ok"));

src/index.js

@@ -5,10 +5,13 @@ const
     onFinished = require("on-finished");
 
 function filterArrayByRegExps(array, regexps) {
-    let compiled = regexps.map(regexp => new RegExp(regexp));
     return array.filter(element => {
-        for (let regexp of compiled) {
-            if (element.match(regexp)) {
+        for (let regexp of regexps) {
+            if (regexp instanceof RegExp) {
+                if (element.match(regexp)) {
+                    return true;
+                }
+            } else if (element == regexp) {
                 return true;
             }
         }