@thi.ng/transducers - npm Package Compare versions

Comparing version 0.5.0 to 0.5.1

index.d.ts

@@ -17,3 +17,13 @@ import { Comparator, IDeref, Predicate } from "@thi.ng/api";
 export declare function unreduced(x: any): any;
-export declare function comp(...fns: ((x: any) => any)[]): (x: any) => any;
+export declare function comp<A, B>(a: Transducer<A, B>): Transducer<A, B>;
+export declare function comp<A, B, C>(a: Transducer<A, B>, b: Transducer<B, C>): Transducer<A, C>;
+export declare function comp<A, B, C, D>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>): Transducer<A, D>;
+export declare function comp<A, B, C, D, E>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>): Transducer<A, E>;
+export declare function comp<A, B, C, D, E, F>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>, e: Transducer<E, F>): Transducer<A, F>;
+export declare function comp<A, B, C, D, E, F, G>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>, e: Transducer<E, F>, f: Transducer<F, G>): Transducer<A, G>;
+export declare function comp<A, B, C, D, E, F, G, H>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>, e: Transducer<E, F>, f: Transducer<F, G>, g: Transducer<G, H>): Transducer<A, H>;
+export declare function comp<A, B, C, D, E, F, G, H, I>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>, e: Transducer<E, F>, f: Transducer<F, G>, g: Transducer<G, H>, h: Transducer<H, I>): Transducer<A, I>;
+export declare function comp<A, B, C, D, E, F, G, H, I, J>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>, e: Transducer<E, F>, f: Transducer<F, G>, g: Transducer<G, H>, h: Transducer<H, I>, i: Transducer<I, J>): Transducer<A, J>;
+export declare function comp<A, B, C, D, E, F, G, H, I, J, K>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>, e: Transducer<E, F>, f: Transducer<F, G>, g: Transducer<G, H>, h: Transducer<H, I>, i: Transducer<I, J>, j: Transducer<J, K>): Transducer<A, K>;
+export declare function comp<A, B, C, D, E, F, G, H, I, J, K>(a: Transducer<A, B>, b: Transducer<B, C>, c: Transducer<C, D>, d: Transducer<D, E>, e: Transducer<E, F>, f: Transducer<F, G>, g: Transducer<G, H>, h: Transducer<H, I>, i: Transducer<I, J>, j: Transducer<J, K>, ...fns: Transducer<any, any>[]): Transducer<A, any>;
 export declare function compR(rfn: Reducer<any, any>, fn: (acc, x) => any): Reducer<any, any>;
@@ -28,3 +38,4 @@ export declare function identity<T>(x: T): T;
 export declare function map<A, B>(fn: (x: A) => B): Transducer<A, B>;
-export declare function selectKeys(...keys: PropertyKey[]): Transducer<any, any>;
+export declare function pluck(key: PropertyKey): Transducer<any, any>;
+export declare function selectKeys(keys: PropertyKey[]): Transducer<any, any>;
 export declare function mapIndexed<A, B>(fn: (i: number, x: A) => B): Transducer<A, B>;
@@ -37,2 +48,3 @@ export declare function mapcat<A, B>(fn: (x: A) => Iterable<B>): Transducer<A, B>;
 export declare function filter<T>(pred: Predicate<T>): Transducer<T, T>;
+export declare function keep<T>(f?: ((x: T) => any)): Transducer<T, T>;
 export declare function throttle<T>(delay: number): Transducer<T, T>;
@@ -39,0 +51,0 @@ export declare function delayed<T>(t: number): Transducer<T, Promise<T>>;

index.js

@@ -143,13 +143,28 @@ "use strict";
 exports.map = map;
-function selectKeys(...keys) {
+function pluck(key) {
+    return map((x) => x[key]);
+}
+exports.pluck = pluck;
+function selectKeys(keys) {
     const [a, b, c] = keys;
     switch (keys.length) {
         case 0:
-            throw new Error(`no keys given`);
+            throw new Error("no keys given");
         case 1:
-            return map((x) => x[a]);
+            return map((x) => x.hasOwnProperty(a) ? { [a]: x[a] } : {});
         case 2:
-            return map((x) => ({ [a]: x[a], [b]: x[b] }));
+            return map((x) => {
+                const res = {};
+                x.hasOwnProperty(a) && (res[a] = x[a]);
+                x.hasOwnProperty(b) && (res[b] = x[b]);
+                return res;
+            });
         case 3:
-            return map((x) => ({ [a]: x[a], [b]: x[b], [c]: x[c] }));
+            return map((x) => {
+                const res = {};
+                x.hasOwnProperty(a) && (res[a] = x[a]);
+                x.hasOwnProperty(b) && (res[b] = x[b]);
+                x.hasOwnProperty(c) && (res[c] = x[c]);
+                return res;
+            });
         default:
@@ -160,3 +175,3 @@ return map((x) => {
                     const k = keys[i];
-                    res[k] = x[k];
+                    x.hasOwnProperty(k) && (res[k] = x[k]);
                 }
@@ -240,2 +255,9 @@ return res;
 exports.filter = filter;
+function keep(f = identity) {
+    return (rfn) => {
+        const r = rfn[2];
+        return compR(rfn, (acc, x) => f(x) != null ? r(acc, x) : acc);
+    };
+}
+exports.keep = keep;
 function throttle(delay) {
@@ -242,0 +264,0 @@ return (rfn) => {

package.json

 {
     "name": "@thi.ng/transducers",
-    "version": "0.5.0",
+    "version": "0.5.1",
     "description": "Lightweight transducer implementations for ES6 / TypeScript",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -7,3 +7,3 @@ # @thi.ng/transducers
 
-The library provides 31 transducers and 14 reducers for composing data
+The library provides 33 transducers and 14 reducers for composing data
 transformation pipelines (more to come).
@@ -257,2 +257,4 @@
 
+#### `pluck(key: PropertyKey): Transducer<any, any>`
+
 #### `scan<A, B>(rfn: Reducer<B, A>, acc?: B): Transducer<A, B>`
@@ -262,2 +264,4 @@
 
+#### `keep<T>(f?: ((x: T) => any)): Transducer<T, T>`
+
 #### `throttle<T>(delay: number): Transducer<T, T>`
@@ -264,0 +268,0 @@

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Found 1 instance in 1 package

Fixed alerts

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Improved metrics

Total package byte prevSize

33462

increased by9.88%

Lines of code

740

increased by4.96%

Number of lines in readme file

338

increased by1.2%

No dependency changes