@ts-common/iterator - npm Package Compare versions

Comparing version 0.0.21 to 0.0.24

index.d.ts

@@ -0,12 +1,20 @@
+import { Tuple2 } from "@ts-common/tuple";
 export declare function iterable<T>(createIterator: () => Iterator<T>): Iterable<T>;
+export declare type Entry<T> = Tuple2<number, T>;
+export declare const entry: <T>(key: number, value: T) => Entry<T>;
+export declare function entries<T>(input: Iterable<T>): Iterable<Entry<T>>;
 export declare function map<T, I>(input: Iterable<I>, func: (v: I, i: number) => T): Iterable<T>;
-export declare function forEach<T>(input: Iterable<T>, func: (v: T, i: number) => void): void;
-export declare function filterMap<T, I>(input: Iterable<I>, func: (v: I, i: number) => T | undefined): Iterable<T>;
-export declare function filter<T>(input: Iterable<T>, func: (v: T) => boolean): Iterable<T>;
 export declare function flatten<T>(input: Iterable<Iterable<T>>): Iterable<T>;
+export declare function takeWhile<T>(input: Iterable<T>, func: (v: T, i: number) => boolean): Iterable<T>;
 export declare function flatMap<T, I>(input: Iterable<I>, func: (v: I, i: number) => Iterable<T>): Iterable<T>;
+export declare function optionalToArray<T>(v: T | undefined): ReadonlyArray<T>;
+export declare function filterMap<T, I>(input: Iterable<I>, func: (v: I, i: number) => T | undefined): Iterable<T>;
+export declare function filter<T>(input: Iterable<T>, func: (v: T, i: number) => boolean): Iterable<T>;
 export declare function generate<T>(func: (i: number) => T, count?: number): Iterable<T>;
 export declare function repeat<T>(v: T, count?: number): Iterable<T>;
-export declare function reduce<T>(input: Iterable<T>, func: (a: T, b: T) => T, init: T): T;
-export declare function reduce<T>(input: Iterable<T>, func: (a: T, b: T) => T): T | undefined;
+export declare function lazyFold<T, A>(input: Iterable<T>, func: (a: A, b: T, i: number) => A, init: A): Iterable<A>;
+export declare function last<T>(input: Iterable<T>): T | undefined;
+export declare function fold<T, A>(input: Iterable<T>, func: (a: A, b: T, i: number) => A, init: A): A;
+export declare function reduce<T>(input: Iterable<T>, func: (a: T, b: T, i: number) => T): T | undefined;
+export declare function forEach<T>(input: Iterable<T>, func: (v: T, i: number) => void): void;
 export declare function sum(input: Iterable<number>): number;
@@ -13,0 +21,0 @@ export declare function min(input: Iterable<number>): number;

index.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
+const tuple_1 = require("@ts-common/tuple");
 function iterable(createIterator) {
-    return {
-        [Symbol.iterator]() { return createIterator(); },
-    };
+    return { [Symbol.iterator]: createIterator };
 }
 exports.iterable = iterable;
-function map(input, func) {
+exports.entry = tuple_1.tuple2;
+function entries(input) {
     function* iterator() {
-        let i = 0;
-        for (const v of input) {
-            yield func(v, i);
-            ++i;
+        let index = 0;
+        /* tslint:disable-next-line:no-loop-statement */
+        for (const value of input) {
+            yield exports.entry(index, value);
+            /* tslint:disable-next-line:no-expression-statement */
+            ++index;
         }
@@ -19,20 +21,8 @@ }
 }
-exports.map = map;
-function forEach(input, func) {
-    let i = 0;
-    for (const v of input) {
-        func(v, i);
-        ++i;
-    }
-}
-exports.forEach = forEach;
-function filterMap(input, func) {
+exports.entries = entries;
+function map(input, func) {
     function* iterator() {
-        let i = 0;
-        for (const v of input) {
-            const result = func(v, i);
-            if (result !== undefined) {
-                yield result;
-            }
-            ++i;
+        /* tslint:disable-next-line:no-loop-statement */
+        for (const [index, value] of entries(input)) {
+            yield func(value, index);
         }
@@ -42,9 +32,8 @@ }
 }
-exports.filterMap = filterMap;
-function filter(input, func) {
+exports.map = map;
+function flatten(input) {
     function* iterator() {
+        /* tslint:disable-next-line:no-loop-statement */
         for (const v of input) {
-            if (func(v)) {
-                yield v;
-            }
+            yield* v;
         }
@@ -54,7 +43,12 @@ }
 }
-exports.filter = filter;
-function flatten(input) {
+exports.flatten = flatten;
+function takeWhile(input, func) {
     function* iterator() {
-        for (const v of input) {
-            yield* v;
+        /* tslint:disable-next-line:no-loop-statement */
+        for (const [index, value] of entries(input)) {
+            /* tslint:disable-next-line:no-if-statement */
+            if (!func(value, index)) {
+                return;
+            }
+            yield value;
         }
@@ -64,3 +58,3 @@ }
 }
-exports.flatten = flatten;
+exports.takeWhile = takeWhile;
 function flatMap(input, func) {
@@ -70,7 +64,19 @@ return flatten(map(input, func));
 exports.flatMap = flatMap;
-function generate(func, count) {
-    const f = count === undefined ? () => true : i => i < count;
+function optionalToArray(v) {
+    return v === undefined ? [] : [v];
+}
+exports.optionalToArray = optionalToArray;
+function filterMap(input, func) {
+    return flatMap(input, (v, i) => optionalToArray(func(v, i)));
+}
+exports.filterMap = filterMap;
+function filter(input, func) {
+    return flatMap(input, (v, i) => func(v, i) ? [v] : []);
+}
+exports.filter = filter;
+function infinite() {
     function* iterator() {
-        for (let i = 0; f(i); ++i) {
-            yield func(i);
+        /* tslint:disable-next-line:no-loop-statement */
+        while (true) {
+            yield;
         }
@@ -80,24 +86,57 @@ }
 }
+function generate(func, count) {
+    return map(takeWhile(infinite(), (_, i) => i !== count), (_, i) => func(i));
+}
 exports.generate = generate;
 function repeat(v, count) {
-    return generate(_ => v, count);
+    return generate(() => v, count);
 }
 exports.repeat = repeat;
-function reduce(input, func, init) {
+function lazyFold(input, func, init) {
+    function* iterator() {
+        let result = init;
+        /* tslint:disable-next-line:no-loop-statement */
+        for (const [index, value] of entries(input)) {
+            /* tslint:disable-next-line:no-expression-statement */
+            result = func(result, value, index);
+            yield result;
+        }
+    }
+    return iterable(iterator);
+}
+exports.lazyFold = lazyFold;
+function last(input) {
+    let result;
+    /* tslint:disable-next-line:no-loop-statement */
     for (const v of input) {
-        init = init === undefined ? v : func(init, v);
+        /* tslint:disable-next-line:no-expression-statement */
+        result = v;
     }
-    return init;
+    return result;
 }
+exports.last = last;
+function fold(input, func, init) {
+    const result = last(lazyFold(input, func, init));
+    return result !== undefined ? result : init;
+}
+exports.fold = fold;
+function reduce(input, func) {
+    return fold(input, (a, b, i) => a !== undefined ? func(a, b, i) : b, undefined);
+}
 exports.reduce = reduce;
+function forEach(input, func) {
+    /* tslint:disable-next-line:no-expression-statement */
+    fold(input, (_, v, i) => { func(v, i); }, undefined);
+}
+exports.forEach = forEach;
 function sum(input) {
-    return reduce(input, (a, b) => a + b, 0);
+    return fold(input, (a, b) => a + b, 0);
 }
 exports.sum = sum;
 function min(input) {
-    return reduce(input, Math.min, Infinity);
+    return fold(input, (a, b) => Math.min(a, b), Infinity);
 }
 exports.min = min;
 function max(input) {
-    return reduce(input, Math.max, -Infinity);
+    return fold(input, (a, b) => Math.max(a, b), -Infinity);
 }
@@ -109,12 +148,14 @@ exports.max = max;
         const iterators = inputs.map(i => i[Symbol.iterator]());
+        /* tslint:disable-next-line:no-loop-statement */
         while (true) {
             const result = new Array(inputs.length);
-            let i = 0;
-            for (const it of iterators) {
+            /* tslint:disable-next-line:no-loop-statement */
+            for (const [index, it] of entries(iterators)) {
                 const v = it.next();
+                /* tslint:disable-next-line:no-if-statement */
                 if (v.done) {
                     return;
                 }
-                result[i] = v.value;
-                ++i;
+                /* tslint:disable-next-line:no-object-mutation no-expression-statement */
+                result[index] = v.value;
             }
@@ -128,5 +169,7 @@ yield result;
 function arrayEqual(a, b, e) {
+    /* tslint:disable-next-line:no-if-statement */
     if (a === b) {
         return true;
     }
+    /* tslint:disable-next-line:no-if-statement */
     if (a === undefined || b === undefined) {
@@ -137,6 +180,9 @@ return false;
     const bl = b.length;
+    /* tslint:disable-next-line:no-if-statement */
     if (al !== bl) {
         return false;
     }
+    /* tslint:disable-next-line:no-loop-statement */
     for (let i = 0; i < al; ++i) {
+        /* tslint:disable-next-line:no-if-statement */
         if (!e(a[i], b[i])) {
@@ -143,0 +189,0 @@ return false;

package.json

 {
   "name": "@ts-common/iterator",
-  "version": "0.0.21",
+  "version": "0.0.24",
   "description": "Iterator library for JavaScript and TypeScript",
@@ -16,3 +16,3 @@ "main": "index.js",
     "prepack": "npm install && tsc",
-    "test": "tsc && nyc mocha"
+    "test": "tsc && npm run tslint && nyc mocha"
   },
@@ -45,3 +45,5 @@ "repository": {
   },
-  "dependencies": {}
+  "dependencies": {
+    "@ts-common/tuple": "0.0.0"
+  }
 }

README.md

@@ -6,1 +6,5 @@ # iterator
 Iterator library for TypeScript and JavaScript
+
+## fold vs reduce
+
+https://stackoverflow.com/questions/25158780/difference-between-reduce-and-foldleft-fold-in-functional-programming-particula

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Improved metrics

Total package byte prevSize

20794

increased by17.57%

Lines of code

209

increased by34.84%

Number of lines in readme file

9

increased by50%

Worsened metrics

Dependency count

1

increased byInfinity%

Dependency changes

• + Added@ts-common/tuple@0.0.0

• + Added@ts-common/tuple@0.0.0(transitive)