lib: validate metrics batch/buffer config inputs

Require positive finite numbers when metricsBatchSize/metricsBufferSize
are set via nsolid.start() or live reconfigure so odd JS values (true,
objects, NaN, etc.) are ignored
Add test-nsolid-start-metrics-buffer.js test to cover for this.

Author: santigimeno

lib/nsolid.js

@@ -6,6 +6,8 @@ const {
   DateNow,
   JSONParse,
   JSONStringify,
+  Number,
+  NumberIsFinite,
   NumberParseInt,
   ObjectAssign,
   ObjectDefineProperty,
@@ -769,6 +771,14 @@ function updateConfig(config = {}) {
       if (normalized !== undefined) {
         nsolidConfig.assetsEnabled = normalized;
       }
+    } else if (key === 'metricsBatchSize' || key === 'metricsBufferSize') {
+      const raw = config[key];
+      if (typeof raw === 'number' || (typeof raw === 'string' && raw.trim() !== '')) {
+        const value = Number(raw);
+        if (NumberIsFinite(value) && value > 0) {
+          nsolidConfig[key] = value;
+        }
+      }
     } else {
       nsolidConfig[key] = config[key];
     }

test/parallel/test-nsolid-start-metrics-buffer.js

@@ -0,0 +1,44 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const nsolid = require('nsolid');
+
+const defaultBatchSize = nsolid.config.metricsBatchSize;
+const defaultBufferSize = nsolid.config.metricsBufferSize;
+
+nsolid.start({
+  metricsBatchSize: defaultBatchSize + 1,
+  metricsBufferSize: defaultBufferSize + 50
+});
+assert.strictEqual(nsolid.config.metricsBatchSize, defaultBatchSize + 1);
+assert.strictEqual(nsolid.config.metricsBufferSize, defaultBufferSize + 50);
+
+nsolid.start({
+  metricsBatchSize: `${defaultBatchSize + 2}`,
+  metricsBufferSize: `${defaultBufferSize + 100}`
+});
+assert.strictEqual(nsolid.config.metricsBatchSize, defaultBatchSize + 2);
+assert.strictEqual(nsolid.config.metricsBufferSize, defaultBufferSize + 100);
+
+// Invalid inputs should be ignored
+const invalidValues = [0, -1, NaN, undefined, null, true, false, {}, [], () => {}];
+for (const value of invalidValues) {
+  nsolid.start({
+    metricsBatchSize: value,
+    metricsBufferSize: value
+  });
+  assert.strictEqual(nsolid.config.metricsBatchSize,
+                     defaultBatchSize + 2,
+                     `metricsBatchSize changed unexpectedly for value: ${String(value)}`);
+  assert.strictEqual(nsolid.config.metricsBufferSize,
+                     defaultBufferSize + 100,
+                     `metricsBufferSize changed unexpectedly for value: ${String(value)}`);
+}
+
+nsolid.start({
+  metricsBatchSize: defaultBatchSize,
+  metricsBufferSize: defaultBufferSize
+});
+assert.strictEqual(nsolid.config.metricsBatchSize, defaultBatchSize);
+assert.strictEqual(nsolid.config.metricsBufferSize, defaultBufferSize);