1 files changed, 20 insertions, 9 deletions
diff --git a/u/trace/itrace.ts b/u/trace/itrace.ts
index b9b750d..620fff0 100644
--- a/u/trace/itrace.ts
+++ b/u/trace/itrace.ts
@@ -1,4 +1,4 @@
-import type { Mapper, SideEffect } from "@emprespresso/pengueno";
+import type { Mapper, SideEffect, Supplier } from "@emprespresso/pengueno";
 
 // the "thing" every Trace writer must "trace()"
 type BaseTraceWith = string;
@@ -19,15 +19,18 @@ export type ITraceableMapper<
 ) => U;
 
 export interface ITraceable<T, Trace = BaseTraceWith> {
-  readonly item: T;
   readonly trace: ITrace<Trace>;
-
+  get: Supplier<T>;
   move<U>(u: U): ITraceable<U, Trace>;
   map: <U>(
     mapper: ITraceableMapper<T, U, Trace>,
   ) => ITraceable<U, Trace>;
   bimap: <U>(
-    mapper: ITraceableMapper<T, ITraceableTuple<U, Trace>, Trace>,
+    mapper: ITraceableMapper<
+      T,
+      ITraceableTuple<U, Array<Trace> | Trace>,
+      Trace
+    >,
   ) => ITraceable<U, Trace>;
   peek: (peek: ITraceableMapper<T, void, Trace>) => ITraceable<T, Trace>;
   flatMap: <U>(
@@ -40,8 +43,8 @@ export interface ITraceable<T, Trace = BaseTraceWith> {
 
 export class TraceableImpl<T, TraceWith> implements ITraceable<T, TraceWith> {
   protected constructor(
-    readonly item: T,
-    readonly trace: ITrace<TraceWith>,
+    private readonly item: T,
+    public readonly trace: ITrace<TraceWith>,
   ) {}
 
   public map<U>(
@@ -69,7 +72,7 @@ export class TraceableImpl<T, TraceWith> implements ITraceable<T, TraceWith> {
     >,
   ): ITraceable<Promise<U>, TraceWith> {
     return new TraceableImpl(
-      mapper(this).then(({ item }) => item),
+      mapper(this).then((t) => t.get()),
       this.trace,
     );
   }
@@ -86,11 +89,19 @@ export class TraceableImpl<T, TraceWith> implements ITraceable<T, TraceWith> {
   public bimap<U>(
     mapper: ITraceableMapper<
       T,
-      ITraceableTuple<U, TraceWith>,
+      ITraceableTuple<U, Array<TraceWith> | TraceWith>,
       TraceWith
     >,
   ) {
     const [item, trace] = mapper(this);
-    return new TraceableImpl(item, this.trace.addTrace(trace));
+    const traces = Array.isArray(trace) ? trace : [trace];
+    return new TraceableImpl(
+      item,
+      traces.reduce((trace, _trace) => trace.addTrace(_trace), this.trace),
+    );
+  }
+
+  public get() {
+    return this.item;
   }
 }