README updated

Author: tsmx

README.md

@@ -12,7 +12,7 @@ Manage JSON based configurations with AES encrypted secrets for multiple environ
 
 Optional features:
 - [HMAC validation](#hmacValidation) of configurations to ensure data integrity
-- Setting of environment variables out of configuration items 
+- Setting of [environment variables](#envVarExports) out of configuration items 
 
 Works with CommonJS and ESM/ECMAScript. Ships with a [SBOM](#SBOM) to meet regulatory requirements.
 
@@ -243,13 +243,11 @@ Depending on the value of `NODE_ENV` the following configuration files will be l
 Type: `Array`
 Default: `[]`
 
-With `envVarExports` you can set environment variables out of configuration items by passing an array of objects each having a `key` and `envVar` property where:
-- `key` is the name of a configuration item
+With the `envVarExports` option (or alternatively the `__envVarExports` configuration key) you can set environment variables out of configuration items by passing an array of objects each having a `key` and `envVar` property where:
+- `key` is the name of a configuration item, if the configuration item is not at the top level of the configuration JSON, simply pass the full path to it using dotted notation (see example below)
 - `envVar` is the name of the environment variable to be set with the value of the configuration item
 - both properties must be of type string
 
-If the configuration item is not at the top level of the configuration JSON, simply pass the full path to it using dotted notation (see example below). 
-
 Suppose you have the following configuation...
 
 ```json
@@ -262,7 +260,9 @@ Suppose you have the following configuation...
  }
 ```
 
-...and need to set the database user and password as environment variables `DB_USER` and `DB_PASSWORD`. Then simply pass the following `envVarExports` array.
+...and need to set the database user and password as environment variables `DB_USER` and `DB_PASSWORD`. Then simply pass the following `envVarExports` array either programmatically or directly in the configuration via the `__envVarExports` key.
+
+Programmatic passing:
 
 ```js
 const envVarExports = [
@@ -272,11 +272,34 @@ const envVarExports = [
 const conf = require('@tsmx/secure-config')({ envVarExports });
 ```
 
-This will automatically set the env vars `DB_USER` and `DB_PASSWORD` with the decrypted configuration item values.
+Passing via configuration:
+
+```JSON
+{
+  "database": {
+    "host": "127.0.0.1",
+    "user": "ENCRYPTED|50ceed2f97223100fbdf842ecbd4541f|df9ed9002bfc956eb14b1d2f8d960a11",
+    "pass": "ENCRYPTED|8fbf6ded36bcb15bd4734b3dc78f2890|7463b2ea8ed2c8d71272ac2e41761a35"
+  },
+  "__envVarExports": [
+    {
+      "key": "database.user",
+      "envVar": "DB_USER"
+    },
+    {
+      "key": "database.pass",
+      "envVar": "DB_PASSWORD"
+    }
+  ]
+}
+```
+
+Both approaches will automatically set the env vars `DB_USER` and `DB_PASSWORD` with the decrypted configuration item values.
 
 Notes:
 - If the `envVarExports` array contains multiple entries having the exact same `key`, only the first entry will be considered.
 - If `envVarExports` contains entries that cannot be found in the configuration, no env var will be set and no error will be thrown.
+- If the `envVarExports` option AND the `__envVarExports` configuration key both are present, the programmatic passed arry will take precedence.
 
 ## Injecting the decryption key
 
@@ -388,10 +411,3 @@ This package ships with a CycloneDX software bill of materials (SBOM) v1.6 in JS
 
 ### 2.3.1
 - [SBOM](#SBOM) added to shipped files
-
-## Test
-
-```
-npm install
-npm test
-```