@thi.ng/transducers - npm Package Compare versions

Comparing version 0.4.0 to 0.5.0

index.d.ts

@@ -37,2 +37,5 @@ import { Comparator, IDeref, Predicate } from "@thi.ng/api";
 export declare function delayed<T>(t: number): Transducer<T, Promise<T>>;
+export declare function bench(): Transducer<any, number>;
+export declare function sideEffect<T>(fn: (x: T) => void): Transducer<T, T>;
+export declare function inspect<T>(prefix?: string): Transducer<T, T>;
 export declare function distinct<T>(mapfn?: ((x: T) => any)): Transducer<T, T>;
@@ -39,0 +42,0 @@ export declare function dedupe<T>(equiv?: (a: T, b: T) => boolean): Transducer<T, T>;

index.js

@@ -257,2 +257,22 @@ "use strict";
 exports.delayed = delayed;
+function bench() {
+    return (rfn) => {
+        const r = rfn[2];
+        let prev;
+        return compR(rfn, (acc, _) => {
+            let t = Date.now(), x = prev ? t - prev : 0;
+            prev = t;
+            r(acc, x);
+        });
+    };
+}
+exports.bench = bench;
+function sideEffect(fn) {
+    return map((x) => (fn(x), x));
+}
+exports.sideEffect = sideEffect;
+function inspect(prefix = "") {
+    return sideEffect((x) => console.log(prefix, x));
+}
+exports.inspect = inspect;
 function distinct(mapfn = identity) {
@@ -271,6 +291,7 @@ return (rfn) => {
 exports.distinct = distinct;
+const SEMAPHORE = Symbol("SEMAPHORE");
 function dedupe(equiv) {
     return (rfn) => {
         const r = rfn[2];
-        let prev = {};
+        let prev = SEMAPHORE;
         return compR(rfn, equiv ?
@@ -277,0 +298,0 @@ (acc, x) => {

package.json

 {
     "name": "@thi.ng/transducers",
-    "version": "0.4.0",
+    "version": "0.5.0",
     "description": "Lightweight transducer implementations for ES6 / TypeScript",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -5,7 +5,11 @@ # @thi.ng/transducers
 
-Lightweight transducer implementations for ES6 / TypeScript (7.6KB minified).
+Lightweight transducer implementations for ES6 / TypeScript (8KB minified, full lib).
 
-The library provides 28 transducers and 14 reducers for composing data
+The library provides 31 transducers and 14 reducers for composing data
 transformation pipelines (more to come).
 
+Please see the [@thi.ng/iterators](https://github.com/thi-ng/iterators) &
+[@thi.ng/csp](https://github.com/thi-ng/csp) partner modules for related
+functionality, supplementing features of this library.
+
 ## Installation
@@ -28,9 +32,12 @@
 
+// collect as array (tx.push)
 tx.transduce(xform, tx.push, [1, 2, 3, 4, 5, 4, 3, 2, 1]);
 // [ 3, 9, 15 ]
 
+// re-use xform, but collect as set (tx.conj)
 tx.transduce(xform, tx.conj, [1, 2, 3, 4, 5, 4, 3, 2, 1]);
 // Set { 3, 9, 15 }
 
-for(let x of tx.iterator(xform, [1, 2, 3, 4])) {
+// apply as transforming iterator
+for(let x of tx.iterator(xform, [1, 2, 3, 4, 5])) {
     console.log(x);
@@ -42,5 +49,29 @@ }
 
+// apply inspectors to debug transducer pipeline
+// alternatively, use tx.sideEffect() for any side fx
+tx.transduce(
+    tx.comp(
+        tx.inspect("orig"),
+        tx.map(x => x + 1),
+        tx.inspect("mapped"),
+        tx.filter(x => (x & 1) > 0)
+    ),
+    tx.push,
+    [1, 2, 3, 4]
+);
+
+// orig 1
+// mapped 2
+// orig 2
+// mapped 3
+// orig 3
+// mapped 4
+// orig 4
+// mapped 5
+// [ 3, 5 ]
+
 tx.transduce(tx.map(x => x.toUpperCase()), tx.frequencies, "hello world")
 // Map { 'H' => 1, 'E' => 1, 'L' => 3, 'O' => 2, ' ' => 1, 'W' => 1, 'R' => 1, 'D' => 1 }
 
+// reduction only (no transform)
 tx.reduce(tx.frequencies, "hello world")
@@ -125,3 +156,3 @@ // Map { 'h' => 1, 'e' => 1, 'l' => 3, 'o' => 2, ' ' => 1, 'w' => 1, 'r' => 1, 'd' => 1 }
     () => [],
-    // completion
+    // completion (nothing to do in this case)
     (acc) => acc,
@@ -133,3 +164,4 @@ // step
 
-Currently only `partition` & `partitionBy` make use of the 1-arity completing function.
+Currently only `partition`, `partitionBy`, `streamSort`, `streamShuffle` make
+use of the 1-arity completing function.
 
@@ -186,3 +218,3 @@ #### Reduced
     return (rfn: Reducer<any, T>) => {
-        // stateful initialization
+        // state initialization
         let prev = {};
@@ -238,2 +270,8 @@ return [
 
+#### `bench(): Transducer<any, number>`
+
+#### `sideEffect<T>(fn: (x: T) => void): Transducer<T, T>`
+
+#### `inspect<T>(prefix?: string): Transducer<T, T>`
+
 #### `distinct<T>(mapfn?: (x: T) => any): Transducer<T, T>`
@@ -240,0 +278,0 @@

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Improved metrics

Total package byte prevSize

30452

increased by5.9%

Lines of code

705

increased by3.52%

Number of lines in readme file

334

increased by12.84%

No dependency changes