@ts-common/iterator - npm Package Compare versions

Comparing version 0.3.4 to 0.3.5

dist/index.d.ts

@@ -134,5 +134,9 @@ /**
     /**
-     * Creates a new sequence of accamulated values.
+     * Creates a new sequence of accumulated values. It's exclusive scan so it always returns at least one value.
      */
     readonly scan: <A>(func: (a: A, b: T, i: number) => A, init: A) => IterableEx<A>;
+    /**
+     * Firstly, the function maps a state and each element using the `func` function, then flattens the result.
+     */
+    readonly flatScan: <A, R>(func: (a: A, b: T, i: number) => readonly [A, Iterable<R>], init: A) => IterableEx<R>;
 };
@@ -160,2 +164,3 @@ export declare const iterable: <T>(createIterator: () => Iterator<T>) => IterableEx<T>;
 export declare const scan: <T, A>(input: Iterable<T> | undefined, func: (a: A, b: T, i: number) => A, init: A) => IterableEx<A>;
+export declare const flatScan: <T, A, R>(input: Iterable<T> | undefined, func: (a: A, b: T, i: number) => readonly [A, Iterable<R>], init: A) => IterableEx<R>;
 export declare const fold: <T, A>(input: Iterable<T> | undefined, func: (a: A, b: T, i: number) => A, init: A) => A;
@@ -162,0 +167,0 @@ export declare const reduce: <T>(input: Iterable<T> | undefined, func: (a: T, b: T, i: number) => T) => T | undefined;

dist/index.js

@@ -32,2 +32,3 @@ "use strict";
         scan: property(exports.scan),
+        flatScan: property(exports.flatScan),
     };
@@ -44,6 +45,6 @@ };
     let index = 0;
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     for (const value of input) {
         yield [index, value];
-        /* tslint:disable-next-line:no-expression-statement */
+        // tslint:disable-next-line:no-expression-statement
         index += 1;
@@ -53,3 +54,3 @@ }
 exports.map = (input, func) => exports.iterable(function* () {
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     for (const [index, value] of exports.entries(input)) {
@@ -65,3 +66,3 @@ yield func(value, index);
     }
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     for (const v of input) {
@@ -76,5 +77,5 @@ // tslint:disable-next-line:no-if-statement
 exports.takeWhile = (input, func) => exports.iterable(function* () {
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     for (const [index, value] of exports.entries(input)) {
-        /* tslint:disable-next-line:no-if-statement */
+        // tslint:disable-next-line:no-if-statement
         if (!func(value, index)) {
@@ -106,3 +107,3 @@ return;
 const infinite = () => exports.iterable(function* () {
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     while (true) {
@@ -119,5 +120,5 @@ yield;
     yield result;
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     for (const [index, value] of exports.entries(input)) {
-        /* tslint:disable-next-line:no-expression-statement */
+        // tslint:disable-next-line:no-expression-statement
         result = func(result, value, index);
@@ -127,7 +128,18 @@ yield result;
 });
+exports.flatScan = (input, func, init) => exports.iterable(function* () {
+    let state = init;
+    // tslint:disable-next-line:no-loop-statement
+    for (const [index, value] of exports.entries(input)) {
+        // tslint:disable-next-line:no-expression-statement
+        const [newState, result] = func(state, value, index);
+        // tslint:disable-next-line:no-expression-statement
+        state = newState;
+        yield* result;
+    }
+});
 exports.fold = (input, func, init) => {
     let result = init;
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     for (const [index, value] of exports.entries(input)) {
-        /* tslint:disable-next-line:no-expression-statement */
+        // tslint:disable-next-line:no-expression-statement
         result = func(result, value, index);
@@ -150,13 +162,13 @@ }
     const iterators = inputs.map(i => i === undefined ? [][Symbol.iterator]() : i[Symbol.iterator]());
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     while (true) {
         const result = new Array(inputs.length);
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         for (const [index, it] of exports.entries(iterators)) {
             const v = it.next();
-            /* tslint:disable-next-line:no-if-statement */
+            // tslint:disable-next-line:no-if-statement
             if (v.done) {
                 return;
             }
-            /* tslint:disable-next-line:no-object-mutation no-expression-statement */
+            // tslint:disable-next-line:no-object-mutation no-expression-statement
             result[index] = v.value;
@@ -213,15 +225,12 @@ }
 exports.dropRight = (i, n = 1) => i === undefined ? exports.empty() : exports.take(i, i.length - n);
-exports.uniq = (i, key = v => v) => exports.iterable(function* () {
-    const set = new Set();
-    // tslint:disable-next-line:no-loop-statement
-    for (const v of i) {
-        const k = key(v);
-        // tslint:disable-next-line:no-if-statement
-        if (!set.has(k)) {
-            // tslint:disable-next-line:no-expression-statement
-            set.add(k);
-            yield v;
-        }
+exports.uniq = (i, key = v => v) => exports.flatScan(i, (set, v) => {
+    const k = key(v);
+    // tslint:disable-next-line:no-if-statement
+    if (!set.has(k)) {
+        // tslint:disable-next-line:no-expression-statement
+        set.add(k);
+        return [set, [v]];
     }
-});
+    return [set, []];
+}, new Set());
 //# sourceMappingURL=index.js.map

package.json

 {
   "name": "@ts-common/iterator",
-  "version": "0.3.4",
+  "version": "0.3.5",
   "description": "Iterator library for JavaScript and TypeScript",
@@ -69,7 +69,7 @@ "main": "dist/index.js",
     "jest-junit": "^6.4.0",
-    "tslint": "^5.16.0",
+    "tslint": "^5.17.0",
     "tslint-immutable": "^5.5.2",
-    "typescript": "^3.4.5"
+    "typescript": "^3.5.1"
   },
   "dependencies": {}
 }

src/index.ts

@@ -137,5 +137,9 @@ /**
     /**
-     * Creates a new sequence of accamulated values.
+     * Creates a new sequence of accumulated values. It's exclusive scan so it always returns at least one value.
      */
     readonly scan: <A>(func: (a: A, b: T, i: number) => A, init: A) => IterableEx<A>,
+    /**
+     * Firstly, the function maps a state and each element using the `func` function, then flattens the result.
+     */
+    readonly flatScan: <A, R>(func: (a: A, b: T, i: number) => readonly [A, Iterable<R>], init: A) => IterableEx<R>,
 }
@@ -173,2 +177,3 @@
         scan: property(scan),
+        flatScan: property(flatScan),
     }
@@ -191,6 +196,6 @@ }
         let index = 0
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         for (const value of input) {
             yield [index, value] as const
-            /* tslint:disable-next-line:no-expression-statement */
+            // tslint:disable-next-line:no-expression-statement
             index += 1
@@ -205,3 +210,3 @@ }
     iterable(function *(): Iterator<T> {
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         for (const [index, value] of entries(input)) {
@@ -221,3 +226,3 @@ yield func(value, index)
         }
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         for (const v of input) {
@@ -239,5 +244,5 @@ // tslint:disable-next-line:no-if-statement
     iterable(function *(): Iterator<T> {
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         for (const [index, value] of entries(input)) {
-            /* tslint:disable-next-line:no-if-statement */
+            // tslint:disable-next-line:no-if-statement
             if (!func(value, index)) {
@@ -298,3 +303,3 @@ return
     iterable(function *(): Iterator<void> {
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         while (true) { yield }
@@ -319,5 +324,5 @@ })
         yield result
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         for (const [index, value] of entries(input)) {
-            /* tslint:disable-next-line:no-expression-statement */
+            // tslint:disable-next-line:no-expression-statement
             result = func(result, value, index)
@@ -328,2 +333,19 @@ yield result
 
+export const flatScan = <T, A, R>(
+    input: Iterable<T> | undefined,
+    func: (a: A, b: T, i: number) => readonly [A, Iterable<R>],
+    init: A
+): IterableEx<R> =>
+    iterable(function *() {
+        let state = init
+        // tslint:disable-next-line:no-loop-statement
+        for (const [index, value] of entries(input)) {
+            // tslint:disable-next-line:no-expression-statement
+            const [newState, result] = func(state, value, index)
+            // tslint:disable-next-line:no-expression-statement
+            state = newState
+            yield *result
+        }
+    })
+
 export const fold = <T, A>(
@@ -335,5 +357,5 @@ input: Iterable<T> | undefined,
     let result: A = init
-    /* tslint:disable-next-line:no-loop-statement */
+    // tslint:disable-next-line:no-loop-statement
     for (const [index, value] of entries(input)) {
-        /* tslint:disable-next-line:no-expression-statement */
+        // tslint:disable-next-line:no-expression-statement
         result = func(result, value, index)
@@ -388,13 +410,13 @@ }
         )
-        /* tslint:disable-next-line:no-loop-statement */
+        // tslint:disable-next-line:no-loop-statement
         while (true) {
             const result = new Array<T>(inputs.length)
-            /* tslint:disable-next-line:no-loop-statement */
+            // 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 */
+                // tslint:disable-next-line:no-if-statement
                 if (v.done) {
                     return
                 }
-                /* tslint:disable-next-line:no-object-mutation no-expression-statement */
+                // tslint:disable-next-line:no-object-mutation no-expression-statement
                 result[index] = v.value
@@ -473,6 +495,5 @@ }
 export const uniq = <T>(i: Iterable<T>, key: (v: T) => unknown = v => v): IterableEx<T> =>
-    iterable(function *() {
-        const set = new Set<unknown>()
-        // tslint:disable-next-line:no-loop-statement
-        for (const v of i) {
+    flatScan(
+        i,
+        (set, v: T): readonly [Set<unknown>, readonly T[]] => {
             const k = key(v)
@@ -483,5 +504,7 @@ // tslint:disable-next-line:no-if-statement
                 set.add(k)
-                yield v
+                return [set, [v]]
             }
-        }
-    })
+            return [set, []]
+        },
+        new Set<unknown>()
+    )

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Improved metrics

Total package byte prevSize

65507

increased by3.89%

Lines of code

860

increased by4.37%

No dependency changes