add colors to node scanner example

examples/node/package.json

@@ -15,5 +15,8 @@
         "build": "npx tsc",
         "lint": "yarn run eslint ./ts/*.ts && yarn run prettier ./ts/*.ts --check",
         "format": "yarn run prettier --write ./ts/*"
+    },
+    "dependencies": {
+        "ansi-colors": "^4.1.3"
     }
 }

examples/node/ts/scanner.ts

@@ -1,6 +1,7 @@
 import * as readline from "readline/promises";
 import * as fs from "fs";
 import * as timer from "timers/promises";
+import * as colors from "ansi-colors";
 import { RF24, CrcLength, DataRate, FifoState } from "@rf24/rf24";
 
 const io = readline.createInterface({
@@ -82,6 +83,21 @@ export class App {
     console.log(divider);
   }
 
+  /**
+   * Print a colored hexadecimal digit to represent the `total` signal count for a single channel.
+   */
+  print_signals(total: number) {
+    if (total == 0) {
+      process.stdout.write("-");
+    } else if (total < 5) {
+      process.stdout.write(colors.green(total.toString(16).toUpperCase()));
+    } else if (total < 10) {
+      process.stdout.write(colors.yellow(total.toString(16).toUpperCase()));
+    } else {
+      process.stdout.write(colors.red(total.toString(16).toUpperCase()));
+    }
+  }
+
   /**
    * The scanner behavior.
    */
@@ -109,7 +125,7 @@ export class App {
         this.radio.flushRx(); // discard any packets (noise) saved in RX FIFO
       }
       const total = caches[channel];
-      process.stdout.write(total > 0 ? total.toString(16) : "-");
+      this.print_signals(total);
 
       channel += 1;
       let endl = false;
@@ -133,7 +149,7 @@ export class App {
     // finish printing current cache of signals
     for (let i = channel; i < CHANNELS; i++) {
       const total = caches[i];
-      process.stdout.write(total > 0 ? total.toString(16) : "-");
+      this.print_signals(total);
     }
   }
 

yarn.lock

@@ -298,6 +298,11 @@ ajv@^6.12.4:
     json-schema-traverse "^0.4.1"
     uri-js "^4.2.2"
 
+ansi-colors@^4.1.3:
+  version "4.1.3"
+  resolved "https://registry.yarnpkg.com/ansi-colors/-/ansi-colors-4.1.3.tgz#37611340eb2243e70cc604cad35d63270d48781b"
+  integrity sha512-/6w/C21Pm1A7aZitlI5Ni/2J6FFQN8i1Cvz3kHABAAbw93v/NlvKdVOqz7CCWz/3iv/JplRSEEZ83XION15ovw==
+
 ansi-styles@^4.1.0:
   version "4.3.0"
   resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-4.3.0.tgz#edd803628ae71c04c85ae7a0906edad34b648937"