feat(): reorder spreading of properties to prioritize preserving cust…

…om-set properties and custom metadata; add note on this to README

README.md

@@ -187,6 +187,16 @@ You can set `MIKROMETRIC_NAMESPACE` and/or `MIKROMETRIC_SERVICE_NAME` respective
 
 **Any values manually passed in will always take precedence**.
 
+## Behavior of output
+
+Output fields will be spread (and potentially deduplicating same-named properties) in the following order:
+
+1. Dynamic metadata (AWS)
+2. Custom static metadata
+3. Properties
+
+A higher number means that fields in that category will persist if any fields have same names in lower-numbered categories.
+
 ## License
 
 MIT. See `LICENSE` file.

package.json

@@ -1,7 +1,7 @@
 {
   "name": "mikrometric",
   "description": "mikrometric is a Lambda-oriented lightweight wrapper for producing AWS CloudWatch Embedded Metric Format-compatible metric logs.",
-  "version": "1.0.5",
+  "version": "1.0.6",
   "author": "Mikael Vesavuori",
   "license": "MIT",
   "main": "./lib/index.js",

src/domain/entities/MikroMetric.ts

@@ -226,9 +226,9 @@ export class MikroMetric {
    */
   private createMetricObject(): MetricObject {
     const completeMetric = this.sortOutput({
-      ...MikroMetric.metric,
+      ...this.createDynamicMetadata(),
       ...MikroMetric.metadataConfig,
-      ...this.createDynamicMetadata()
+      ...MikroMetric.metric
     });
 
     const filtered = this.filterMetadata(completeMetric);

tests/MikroMetric.test.ts

@@ -103,6 +103,7 @@ test.serial('It should set AWS metadata with provided "event" and "context" obje
   };
 
   const result: any = mikroMetric.flush();
+  console.log('result', result);
   delete result['_aws'];
   delete result['id'];
   delete result['timestamp'];
@@ -135,6 +136,22 @@ test.serial('It should set AWS metadata from environment', (t) => {
   clearEnv();
 });
 
+test.serial(
+  'It should keep directly set/put properties in output if the property name overlap with dynamic metadata',
+  (t) => {
+    setEnv();
+
+    const expected = 'Sam Person';
+    const mikroMetric = MikroMetric.start(config);
+
+    mikroMetric.putMetric('user', expected);
+    const result: any = mikroMetric.flush().user;
+
+    t.deepEqual(result, expected);
+    clearEnv();
+  }
+);
+
 test.serial('It should work without AWS metadata', (t) => {
   const mikroMetric = MikroMetric.start(configMinimal);