Initial import of verae-zapier-simulator from zapier monorepo

src/trace.js

@@ -0,0 +1,44 @@
+/**
+ * Ordered hop log from Zapier input through every module to the response.
+ * @module trace
+ */
+
+export class TraceBus {
+  constructor() {
+    this.events = [];
+    this.t0 = Date.now();
+  }
+
+  now() {
+    return Date.now() - this.t0;
+  }
+
+  /**
+   * @param {{
+   *   module: string,
+   *   hop: string,
+   *   dir?: 'in'|'out'|'internal',
+   *   address?: string,
+   *   status?: 'ok'|'silent'|'error'|'retry'|'delay'|'skip',
+   *   payload?: object,
+   *   note?: string,
+   *   durationMs?: number
+   * }} e
+   */
+  emit(e) {
+    const ev = {
+      seq: this.events.length + 1,
+      tMs: this.now(),
+      module: e.module,
+      hop: e.hop,
+      dir: e.dir || 'internal',
+      address: e.address || '',
+      status: e.status || 'ok',
+      payload: e.payload ?? null,
+      note: e.note || '',
+      durationMs: e.durationMs ?? 0,
+    };
+    this.events.push(ev);
+    return ev;
+  }
+}