chore: add basic tracer example (#277)

examples/node-basic/index.js

@@ -0,0 +1,31 @@
+'use strict';
+
+const opentelemetry = require('@opentelemetry/core');
+const { BasicTracer } = require('@opentelemetry/basic-tracer');
+
+// Initialize the OpenTelemetry APIs to use the BasicTracer bindings
+opentelemetry.initGlobalTracer(new BasicTracer());
+
+// Create a span. A span must be closed.
+const span = opentelemetry.getTracer().startSpan('main');
+for (let i = 0; i < 10; i++) {
+  doWork(span);
+}
+// Be sure to end the span.
+span.end();
+
+function doWork (parent) {
+  // Start another span. In this example, the main method already started a
+  // span, so that'll be the parent span, and this will be a child span.
+  const span = opentelemetry.getTracer().startSpan('doWork', {
+    parent: parent
+  });
+
+  for (let i = 0; i <= 40000000; i++) {} // short delay
+
+  // Set attributes to the span.
+  span.setAttribute('key', 'value');
+
+  // Annotate our span to capture metadata about our operation
+  span.addEvent('invoking doWork').end();
+}