fiter - npm Package Compare versions

Comparing version 0.0.2 to 0.0.3

package.json

 {
   "name": "fiter",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "description": "",
@@ -5,0 +5,0 @@ "main": "./src/index.js",

README.md

@@ -72,2 +72,11 @@ # Fiter
 
+### reduce
+
+Analagous to the `Array.prototype.reduce` method, fiter provides its own reduce that works on any sync/async iterable value. If the iterable is synchronous the value is returned synchronously. If the iterable is async a Promise of the value is returned.
+
+```javascript
+const file = fs.createReadStream('./somefilepath.txt');
+const lines = await reduce(file, (acc, value) => acc + countNewLineCharacters(chunk), 0);
+```
+
 ### find
@@ -74,0 +83,0 @@

src/index.d.ts

@@ -27,2 +27,11 @@ export declare function map<T, K>(it: Iterable<T>, fn: (value: T) => K): Iterable<K>;
 
+export declare function reduce<T, K>(it: Iterable<T>, fn: (acc: T | undefined, value: T) => T): T | undefined;
+export declare function reduce<T, K>(it: Iterable<T>, fn: (acc: K, value: T) => K, initialAcc: K): K;
+export declare function reduce<T, K>(it: AsyncIterable<T>, fn: (acc: T, value: T) => T): Promise<T | undefined>;
+export declare function reduce<T, K>(
+  it: AsyncIterable<T>,
+  fn: (acc: K, value: T) => K,
+  initialAcc: K
+): K extends Promise<any> ? K : Promise<K>;
+
 type Iter = Iterable<any> | AsyncIterable<any>;
@@ -29,0 +38,0 @@ type IsAsyncIterResultType<T extends Iter[]> = {

src/index.js

@@ -122,2 +122,37 @@ 'use strict';
 
+function syncReduce(iter, fn, acc) {
+  if (acc === undefined) {
+    const { value, done } = iter.next();
+    if (done) {
+      return value;
+    }
+    acc = value;
+  }
+  for (const value of iter) {
+    acc = fn(acc, value);
+  }
+  return acc;
+}
+
+async function asyncReduce(iter, fn, acc) {
+  if (acc === undefined) {
+    const { value, done } = await iter.next();
+    if (done) {
+      return value;
+    }
+    acc = value;
+  }
+  for await (const value of iter) {
+    acc = fn(acc, value);
+  }
+  return acc;
+}
+
+function reduce(iter, fn, acc) {
+  if (iter[Symbol.asyncIterator]) {
+    return asyncReduce(iter[Symbol.asyncIterator](), fn, acc);
+  }
+  return syncReduce(iter[Symbol.iterator](), fn, acc);
+}
+
 module.exports = {
@@ -129,4 +164,5 @@ map,
   find,
+  reduce,
   flatMap,
   flat,
 };

No alert changes

Improved metrics

Total package byte prevSize

10510

increased by18.29%

Lines of code

187

increased by28.08%

Number of lines in readme file

164

increased by5.81%

No dependency changes