@pacote/linked-list - npm Package Compare versions

Comparing version 0.1.0 to 0.2.0

CHANGELOG.md

@@ -6,2 +6,8 @@ # Change Log
 
+# [0.2.0](https://github.com/PacoteJS/pacote/compare/@pacote/linked-list@0.1.0...@pacote/linked-list@0.2.0) (2020-09-11)
+
+### Features
+
+- 🎸 adds flatMap function ([f23dedc](https://github.com/PacoteJS/pacote/commit/f23dedce0952205cdd1cbb7d5bdc4561be379c37))
+
 # 0.1.0 (2020-09-05)
@@ -8,0 +14,0 @@

lib/cjs/core.d.ts

@@ -5,6 +5,6 @@ import { Option } from '@pacote/option';
 export declare type LinkedList<T> = Cons<T> | Empty;
-declare type FunctionArgs<T> = [value: T, index: number, collection: LinkedList<T>];
-declare type MapFunction<T, R> = (...args: FunctionArgs<T>) => R;
-export declare type PredicateFunction<T> = MapFunction<T, boolean>;
-declare type ReduceFn<T, R> = (acc: R, ...args: FunctionArgs<T>) => R;
+declare type CallbackArgs<T> = [value: T, index: number, collection: LinkedList<T>];
+declare type MapCallback<T, R> = (...args: CallbackArgs<T>) => R;
+declare type ReduceCallback<T, R> = (acc: R, ...args: CallbackArgs<T>) => R;
+export declare type PredicateFunction<T> = MapCallback<T, boolean>;
 export declare function car<T>(cons: Cons<T>): T;
@@ -16,5 +16,6 @@ export declare function cdr<T>(cons: Cons<T> | Empty): Cons<T> | Empty;
 export declare function append<T>(value: T, list: LinkedList<T>): LinkedList<T>;
-export declare function reduce<T, R>(reducer: ReduceFn<T, R>, initial: R, list: LinkedList<T>): R;
-export declare function reduceRight<T, R>(reducer: ReduceFn<T, R>, initial: R, list: LinkedList<T>): R;
-export declare function map<T, R>(mapper: MapFunction<T, R>, list: LinkedList<T>): LinkedList<R>;
+export declare function reduce<T, R>(callback: ReduceCallback<T, R>, initial: R, list: LinkedList<T>): R;
+export declare function reduceRight<T, R>(callback: ReduceCallback<T, R>, initial: R, list: LinkedList<T>): R;
+export declare function map<T, R>(callback: MapCallback<T, R>, list: LinkedList<T>): LinkedList<R>;
+export declare function flatMap<T, R>(callback: MapCallback<T, LinkedList<R>>, list: LinkedList<T>): LinkedList<R>;
 export declare function filter<T>(predicate: PredicateFunction<T>, list: LinkedList<T>): LinkedList<T>;
@@ -21,0 +22,0 @@ export declare function reverse<T>(list: LinkedList<T>): LinkedList<T>;

lib/cjs/core.js

 "use strict";
 exports.__esModule = true;
-exports.tail = exports.head = exports.concat = exports.length = exports.reverse = exports.filter = exports.map = exports.reduceRight = exports.reduce = exports.append = exports.prepend = exports.isEmpty = exports.emptyList = exports.cdr = exports.car = void 0;
+exports.tail = exports.head = exports.concat = exports.length = exports.reverse = exports.filter = exports.flatMap = exports.map = exports.reduceRight = exports.reduce = exports.append = exports.prepend = exports.isEmpty = exports.emptyList = exports.cdr = exports.car = void 0;
 var option_1 = require("@pacote/option");
@@ -29,22 +29,28 @@ function car(cons) {
 exports.append = append;
-function recursiveReduce(acc, reducer, current, step, index, collection) {
+function recursiveReduce(acc, callback, current, step, index, collection) {
     return isEmpty(current)
         ? acc
-        : recursiveReduce(reducer(acc, car(current), index, collection), reducer, cdr(current), step, index + step, collection);
+        : recursiveReduce(callback(acc, car(current), index, collection), callback, cdr(current), step, index + step, collection);
 }
-function reduce(reducer, initial, list) {
-    return recursiveReduce(initial, reducer, list, 1, 0, list);
+function reduce(callback, initial, list) {
+    return recursiveReduce(initial, callback, list, 1, 0, list);
 }
 exports.reduce = reduce;
-function reduceRight(reducer, initial, list) {
+function reduceRight(callback, initial, list) {
     var lastIndex = length(list) - 1;
-    return recursiveReduce(initial, reducer, reverse(list), -1, lastIndex, list);
+    return recursiveReduce(initial, callback, reverse(list), -1, lastIndex, list);
 }
 exports.reduceRight = reduceRight;
-function map(mapper, list) {
+function map(callback, list) {
     return reverse(reduce(function (acc, value, index, collection) {
-        return prepend(mapper(value, index, collection), acc);
+        return prepend(callback(value, index, collection), acc);
     }, emptyList(), list));
 }
 exports.map = map;
+function flatMap(callback, list) {
+    return reverse(reduce(function (acc, value, index, collection) {
+        return concat(reverse(callback(value, index, collection)), acc);
+    }, emptyList(), list));
+}
+exports.flatMap = flatMap;
 function filter(predicate, list) {
@@ -51,0 +57,0 @@ return reverse(reduce(function (acc, value, index, collection) {

lib/cjs/index.d.ts

@@ -1,2 +0,2 @@
-export { append, cdr as rest, concat, filter, head, isEmpty, length, map, prepend, reduce, reduceRight, reverse, tail, } from './core';
+export { append, cdr as rest, concat, filter, flatMap, head, isEmpty, length, map, prepend, reduce, reduceRight, reverse, tail, } from './core';
 export { every, find, findIndex, get, includes, indexOf, lastIndexOf, some, } from './find';
@@ -3,0 +3,0 @@ export { listOf, toArray } from './array';

lib/cjs/index.js

@@ -10,3 +10,3 @@ "use strict";
 exports.__esModule = true;
-exports.sort = exports.remove = exports.slice = exports.values = exports.keys = exports.entries = exports.toArray = exports.listOf = exports.some = exports.lastIndexOf = exports.indexOf = exports.includes = exports.get = exports.findIndex = exports.find = exports.every = exports.tail = exports.reverse = exports.reduceRight = exports.reduce = exports.prepend = exports.map = exports.length = exports.isEmpty = exports.head = exports.filter = exports.concat = exports.rest = exports.append = void 0;
+exports.sort = exports.remove = exports.slice = exports.values = exports.keys = exports.entries = exports.toArray = exports.listOf = exports.some = exports.lastIndexOf = exports.indexOf = exports.includes = exports.get = exports.findIndex = exports.find = exports.every = exports.tail = exports.reverse = exports.reduceRight = exports.reduce = exports.prepend = exports.map = exports.length = exports.isEmpty = exports.head = exports.flatMap = exports.filter = exports.concat = exports.rest = exports.append = void 0;
 var core_1 = require("./core");
@@ -17,2 +17,3 @@ __createBinding(exports, core_1, "append");
 __createBinding(exports, core_1, "filter");
+__createBinding(exports, core_1, "flatMap");
 __createBinding(exports, core_1, "head");
@@ -19,0 +20,0 @@ __createBinding(exports, core_1, "isEmpty");

lib/esm/core.d.ts

@@ -5,6 +5,6 @@ import { Option } from '@pacote/option';
 export declare type LinkedList<T> = Cons<T> | Empty;
-declare type FunctionArgs<T> = [value: T, index: number, collection: LinkedList<T>];
-declare type MapFunction<T, R> = (...args: FunctionArgs<T>) => R;
-export declare type PredicateFunction<T> = MapFunction<T, boolean>;
-declare type ReduceFn<T, R> = (acc: R, ...args: FunctionArgs<T>) => R;
+declare type CallbackArgs<T> = [value: T, index: number, collection: LinkedList<T>];
+declare type MapCallback<T, R> = (...args: CallbackArgs<T>) => R;
+declare type ReduceCallback<T, R> = (acc: R, ...args: CallbackArgs<T>) => R;
+export declare type PredicateFunction<T> = MapCallback<T, boolean>;
 export declare function car<T>(cons: Cons<T>): T;
@@ -16,5 +16,6 @@ export declare function cdr<T>(cons: Cons<T> | Empty): Cons<T> | Empty;
 export declare function append<T>(value: T, list: LinkedList<T>): LinkedList<T>;
-export declare function reduce<T, R>(reducer: ReduceFn<T, R>, initial: R, list: LinkedList<T>): R;
-export declare function reduceRight<T, R>(reducer: ReduceFn<T, R>, initial: R, list: LinkedList<T>): R;
-export declare function map<T, R>(mapper: MapFunction<T, R>, list: LinkedList<T>): LinkedList<R>;
+export declare function reduce<T, R>(callback: ReduceCallback<T, R>, initial: R, list: LinkedList<T>): R;
+export declare function reduceRight<T, R>(callback: ReduceCallback<T, R>, initial: R, list: LinkedList<T>): R;
+export declare function map<T, R>(callback: MapCallback<T, R>, list: LinkedList<T>): LinkedList<R>;
+export declare function flatMap<T, R>(callback: MapCallback<T, LinkedList<R>>, list: LinkedList<T>): LinkedList<R>;
 export declare function filter<T>(predicate: PredicateFunction<T>, list: LinkedList<T>): LinkedList<T>;
@@ -21,0 +22,0 @@ export declare function reverse<T>(list: LinkedList<T>): LinkedList<T>;

lib/esm/core.js

@@ -20,17 +20,20 @@ import { None, Some } from '@pacote/option';
 }
-function recursiveReduce(acc, reducer, current, step, index, collection) {
+function recursiveReduce(acc, callback, current, step, index, collection) {
     return isEmpty(current)
         ? acc
-        : recursiveReduce(reducer(acc, car(current), index, collection), reducer, cdr(current), step, index + step, collection);
+        : recursiveReduce(callback(acc, car(current), index, collection), callback, cdr(current), step, index + step, collection);
 }
-export function reduce(reducer, initial, list) {
-    return recursiveReduce(initial, reducer, list, 1, 0, list);
+export function reduce(callback, initial, list) {
+    return recursiveReduce(initial, callback, list, 1, 0, list);
 }
-export function reduceRight(reducer, initial, list) {
+export function reduceRight(callback, initial, list) {
     const lastIndex = length(list) - 1;
-    return recursiveReduce(initial, reducer, reverse(list), -1, lastIndex, list);
+    return recursiveReduce(initial, callback, reverse(list), -1, lastIndex, list);
 }
-export function map(mapper, list) {
-    return reverse(reduce((acc, value, index, collection) => prepend(mapper(value, index, collection), acc), emptyList(), list));
+export function map(callback, list) {
+    return reverse(reduce((acc, value, index, collection) => prepend(callback(value, index, collection), acc), emptyList(), list));
 }
+export function flatMap(callback, list) {
+    return reverse(reduce((acc, value, index, collection) => concat(reverse(callback(value, index, collection)), acc), emptyList(), list));
+}
 export function filter(predicate, list) {
@@ -37,0 +40,0 @@ return reverse(reduce((acc, value, index, collection) => predicate(value, index, collection) ? prepend(value, acc) : acc, emptyList(), list));

lib/esm/index.d.ts

@@ -1,2 +0,2 @@
-export { append, cdr as rest, concat, filter, head, isEmpty, length, map, prepend, reduce, reduceRight, reverse, tail, } from './core';
+export { append, cdr as rest, concat, filter, flatMap, head, isEmpty, length, map, prepend, reduce, reduceRight, reverse, tail, } from './core';
 export { every, find, findIndex, get, includes, indexOf, lastIndexOf, some, } from './find';
@@ -3,0 +3,0 @@ export { listOf, toArray } from './array';

lib/esm/index.js

@@ -1,2 +0,2 @@
-export { append, cdr as rest, concat, filter, head, isEmpty, length, map, prepend, reduce, reduceRight, reverse, tail, } from './core';
+export { append, cdr as rest, concat, filter, flatMap, head, isEmpty, length, map, prepend, reduce, reduceRight, reverse, tail, } from './core';
 export { every, find, findIndex, get, includes, indexOf, lastIndexOf, some, } from './find';
@@ -3,0 +3,0 @@ export { listOf, toArray } from './array';

package.json

 {
   "name": "@pacote/linked-list",
   "description": "Immutable linked lists.",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "sideEffects": false,
@@ -39,3 +39,3 @@ "license": "MIT",
   },
-  "gitHead": "4c4d0ed47596a23b39f35e4f4ba4ff36481d6aa9"
+  "gitHead": "dd9d67802b3876ccf42faa5d45970af71187eebb"
 }

README.md

@@ -78,21 +78,26 @@ # @pacote/linked-list
 
-### `map<T, R>(mapper: (element: T, index: number, collection: LinkedList<T>) => R, list: LinkedList<T>): LinkedList<R>`
+### `map<T, R>(callback: (element: T, index: number, collection: LinkedList<T>) => R, list: LinkedList<T>): LinkedList<R>`
 
 `map()` iterates over all items in the provided list and evaluates each element
-through the `mapper` function, returning a new list containing the resulting
+through the `callback` function, returning a new list containing the resulting
 values.
 
-### `reduce<T, R>(reducer: (accumulator: R, element: T, index: number, collection: LinkedList<T>) => R, initial: R, list: LinkedList<T>): R`
+### `flatMap<T, R>(callback: (element: T, index: number, collection: LinkedList<T>) => LinkedList<R>, list: LinkedList<T>): LinkedList<R>`
 
-`reduce()` executes the provided `reducer` function on each element of the list,
-resulting in a single output value, which gets successively passed to the
-`reducer` function in the next execution.
+`flatMap()` iterates over all items in the provided list and evaluates each
+element through the `callback` function and flattening the result by one level.
 
-The first time the `reducer` function is executed, it receives the `initial`
+### `reduce<T, R>(callback: (accumulator: R, element: T, index: number, collection: LinkedList<T>) => R, initial: R, list: LinkedList<T>): R`
+
+`reduce()` executes the provided `callback` function on each element of the
+list, resulting in a single output value, which gets successively passed to the
+`callback` function in the next execution.
+
+The first time the `callback` function is executed, it receives the `initial`
 value.
 
-The result of the last execution of the `reducer` function is returned by
+The result of the last execution of the `callback` function is returned by
 `reduce()`.
 
-### `reduceRight<T, R>(reducer: (accumulator: R, element: T, index: number, collection: LinkedList<T>) => R, initial: R, list: LinkedList<T>): R`
+### `reduceRight<T, R>(callback: (accumulator: R, element: T, index: number, collection: LinkedList<T>) => R, initial: R, list: LinkedList<T>): R`
 
@@ -99,0 +104,0 @@ `reduceRight()` works like `reduce()`, but the list is iterated starting at the

src/core.ts

@@ -7,6 +7,6 @@ import { None, Option, Some } from '@pacote/option'
 
-type FunctionArgs<T> = [value: T, index: number, collection: LinkedList<T>]
-type MapFunction<T, R> = (...args: FunctionArgs<T>) => R
-export type PredicateFunction<T> = MapFunction<T, boolean>
-type ReduceFn<T, R> = (acc: R, ...args: FunctionArgs<T>) => R
+type CallbackArgs<T> = [value: T, index: number, collection: LinkedList<T>]
+type MapCallback<T, R> = (...args: CallbackArgs<T>) => R
+type ReduceCallback<T, R> = (acc: R, ...args: CallbackArgs<T>) => R
+export type PredicateFunction<T> = MapCallback<T, boolean>
 
@@ -39,3 +39,3 @@ export function car<T>(cons: Cons<T>): T {
   acc: R,
-  reducer: ReduceFn<T, R>,
+  callback: ReduceCallback<T, R>,
   current: LinkedList<T>,
@@ -49,4 +49,4 @@ step: number,
     : recursiveReduce(
-        reducer(acc, car(current), index, collection),
-        reducer,
+        callback(acc, car(current), index, collection),
+        callback,
         cdr(current),
@@ -60,11 +60,11 @@ step,
 export function reduce<T, R>(
-  reducer: ReduceFn<T, R>,
+  callback: ReduceCallback<T, R>,
   initial: R,
   list: LinkedList<T>
 ): R {
-  return recursiveReduce(initial, reducer, list, 1, 0, list)
+  return recursiveReduce(initial, callback, list, 1, 0, list)
 }
 
 export function reduceRight<T, R>(
-  reducer: ReduceFn<T, R>,
+  callback: ReduceCallback<T, R>,
   initial: R,
@@ -74,7 +74,7 @@ list: LinkedList<T>
   const lastIndex = length(list) - 1
-  return recursiveReduce(initial, reducer, reverse(list), -1, lastIndex, list)
+  return recursiveReduce(initial, callback, reverse(list), -1, lastIndex, list)
 }
 
 export function map<T, R>(
-  mapper: MapFunction<T, R>,
+  callback: MapCallback<T, R>,
   list: LinkedList<T>
@@ -85,3 +85,3 @@ ): LinkedList<R> {
       (acc, value, index, collection) =>
-        prepend(mapper(value, index, collection), acc),
+        prepend(callback(value, index, collection), acc),
       emptyList(),
@@ -93,2 +93,16 @@ list
 
+export function flatMap<T, R>(
+  callback: MapCallback<T, LinkedList<R>>,
+  list: LinkedList<T>
+): LinkedList<R> {
+  return reverse(
+    reduce(
+      (acc, value, index, collection) =>
+        concat(reverse(callback(value, index, collection)), acc),
+      emptyList(),
+      list
+    )
+  )
+}
+
 export function filter<T>(
@@ -95,0 +109,0 @@ predicate: PredicateFunction<T>,

src/index.ts

@@ -6,2 +6,3 @@ export {
   filter,
+  flatMap,
   head,
@@ -8,0 +9,0 @@ isEmpty,

test/index.spec.ts

@@ -236,13 +236,13 @@ import * as fc from 'fast-check'
 
-  test('calls the mapper function for every item in the list', () => {
+  test('calls the callback function for every item in the list', () => {
     fc.assert(
       fc.property(arbitraryArray, (items) => {
         const list = L.listOf(...items)
-        const mapper = jest.fn()
+        const callback = jest.fn()
 
-        L.map(mapper, list)
+        L.map(callback, list)
 
-        expect(mapper).toHaveBeenCalledTimes(items.length)
+        expect(callback).toHaveBeenCalledTimes(items.length)
         items.forEach((item, index) =>
-          expect(mapper).toHaveBeenCalledWith(item, index, list)
+          expect(callback).toHaveBeenCalledWith(item, index, list)
         )
@@ -254,7 +254,41 @@ })
   test('creates a new list with the items of the list transformed', () => {
-    const mapper = (i: number) => i + 1
-    expect(L.map(mapper, L.listOf(1, 2, 3))).toEqual(L.listOf(2, 3, 4))
+    const callback = (i: number) => i + 1
+    expect(L.map(callback, L.listOf(1, 2, 3))).toEqual(L.listOf(2, 3, 4))
   })
 })
 
+describe('flatMap()', () => {
+  test('returns an empty list unchanged', () => {
+    const list = L.listOf()
+    expect(L.flatMap((i) => L.listOf(i), list)).toEqual(list)
+  })
+
+  test('calls the callback function for every item in the list', () => {
+    fc.assert(
+      fc.property(arbitraryArray, (items) => {
+        const list = L.listOf(...items)
+        const callback = jest.fn()
+
+        L.flatMap(callback, list)
+
+        expect(callback).toHaveBeenCalledTimes(items.length)
+        items.forEach((item, index) =>
+          expect(callback).toHaveBeenCalledWith(item, index, list)
+        )
+      })
+    )
+  })
+
+  test('linked list results are flattened', () => {
+    const list = L.listOf(1, 2, 3)
+    expect(L.flatMap((i) => L.listOf(i), list)).toEqual(list)
+  })
+
+  test('linked list results are flattened in the right order', () => {
+    const list = L.listOf(1, 2, 3)
+    const expected = L.listOf(1.1, 1.2, 2.1, 2.2, 3.1, 3.2)
+    expect(L.flatMap((i) => L.listOf(i + 0.1, i + 0.2), list)).toEqual(expected)
+  })
+})
+
 describe('reduce()', () => {
@@ -266,12 +300,12 @@ test('returns the initial value for an empty list', () => {
 
-  test('calls the reducer function for every item in the list', () => {
+  test('calls the callback function for every item in the list', () => {
     const list = L.listOf(1, 2, 3)
-    const reducer = jest.fn((acc, i) => acc + i)
+    const callback = jest.fn((acc, i) => acc + i)
 
-    L.reduce(reducer, 0, list)
+    L.reduce(callback, 0, list)
 
-    expect(reducer).toHaveBeenCalledTimes(3)
-    expect(reducer).toHaveBeenCalledWith(0, 1, 0, list)
-    expect(reducer).toHaveBeenCalledWith(1, 2, 1, list)
-    expect(reducer).toHaveBeenCalledWith(3, 3, 2, list)
+    expect(callback).toHaveBeenCalledTimes(3)
+    expect(callback).toHaveBeenCalledWith(0, 1, 0, list)
+    expect(callback).toHaveBeenCalledWith(1, 2, 1, list)
+    expect(callback).toHaveBeenCalledWith(3, 3, 2, list)
   })
@@ -292,12 +326,12 @@
 
-  test('calls the reducer function for every item in the list', () => {
+  test('calls the callback function for every item in the list', () => {
     const list = L.listOf(1, 2, 3)
-    const reducer = jest.fn((acc, i) => acc + i)
+    const callback = jest.fn((acc, i) => acc + i)
 
-    L.reduceRight(reducer, 0, list)
+    L.reduceRight(callback, 0, list)
 
-    expect(reducer).toHaveBeenCalledTimes(3)
-    expect(reducer).toHaveBeenCalledWith(0, 3, 2, list)
-    expect(reducer).toHaveBeenCalledWith(3, 2, 1, list)
-    expect(reducer).toHaveBeenCalledWith(5, 1, 0, list)
+    expect(callback).toHaveBeenCalledTimes(3)
+    expect(callback).toHaveBeenCalledWith(0, 3, 2, list)
+    expect(callback).toHaveBeenCalledWith(3, 2, 1, list)
+    expect(callback).toHaveBeenCalledWith(5, 1, 0, list)
   })
@@ -304,0 +338,0 @@

No alert changes

Improved metrics

Total package byte prevSize

72154

increased by4.03%

Lines of code

1653

increased by3.38%

Number of lines in readme file

195

increased by2.63%

No dependency changes