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reverse-iterable-map

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reverse-iterable-map - npm Package Compare versions

Comparing version

2.0.1
to
3.0.0

2

package.json
{
"name": "reverse-iterable-map",
"version": "2.0.1",
"version": "3.0.0",
"description": "A reverse-iterable map implementation based on the built-in Map object",

@@ -5,0 +5,0 @@ "main": "./src/reverse-iterable-map",

368

README.md

@@ -5,2 +5,4 @@ # reverse-iterable-map

It implements a linked list meaning that each element in the internal data structure (a `Map` object) knows about its previous and next element; thus, allowing iteration in both directions *at the same time*. This implies added memory usage because in addition to its key and value, an element also needs to store the two references for the previous and next elements.
Links:

@@ -28,16 +30,17 @@

* [Constructor](#constructor)
* [`size`](#size)
* [`clear()`](#clear)
* [`delete()`](#delete)
* [`entries()`](#entries)
* [`forEach()`](#foreach)
* [`forEachReverse()`](#foreachreverse)
* [`get()`](#get)
* [`has()`](#has)
* [`get()`](#get)
* [`iteratorFor()`](#iteratorfor)
* [`keys()`](#keys)
* [`reverseIterator()`](#reverseiterator)
* [`set()`](#set)
* [`setFirst()`](#setfirst)
* [`delete()`](#delete)
* [`forEach()`](#foreach)
* [`forEachReverse()`](#foreachreverse)
* [`[Symbol.iterator]()`](#symboliterator)
* [`reverse()`](#reverse)
* [`entries()`](#entries)
* [`keys()`](#keys)
* [`values()`](#values)
* [`iteratorFor()`](#iteratorfor)
* [Why this was implemented](#why-this-was-implemented)

@@ -158,2 +161,29 @@ * [How to update this package](#how-to-update-this-package)

### `size`
The `size` accessor property returns the number of elements in a `ReverseIterableMap` object.
#### Syntax
```
map.size
```
#### Usage
```js
const map = new ReverseIterableMap();
map
.set('one', 'I')
.set('two', 'lack')
.set('three', 'creativity');
map.size
//> 3
```
### `clear()`

@@ -181,3 +211,3 @@

### `has()`
### `delete()`

@@ -187,3 +217,3 @@ #### Syntax

```
map.has(key);
map.delete(key);
```

@@ -193,7 +223,7 @@

* **key**: Required. The key of the element to test for presence in the `ReverseIterableMap` object.
* **key**: Required. The key of the element to remove from the `ReverseIterableMap` object.
**Return value**:
* **Boolean**: Returns `true` if an element with the specified key exists in the `ReverseIterableMap` object; otherwise `false`.
* **Boolean**: Returns `true` if an element in the `ReverseIterableMap` object existed and has been removed, or `false` if the element does not exist.

@@ -205,10 +235,10 @@ #### Usage

map.has(0);
//> true
map.delete(0);
//> true (deletes the key value pair [0, 'hey'])
map.has(1);
//> true
map.delete(1);
//> true (deletes the key value pair [1, 'beauty'])
map.has(2);
//> false
map.delete(2);
//> false (key 2 does not exist in map)
```

@@ -218,41 +248,28 @@

### `get()`
### `entries()`
Returns an iterator containing the `[key, value]` pairs for each element in the `ReverseIterableMap` object in insertion order.
An iterator containing the same pairs in reverse-insertion order can be obtained with `entries().reverseIterator()`.
#### Syntax
```
map.get(key);
map.entries();
```
**Parameters**:
* **key**: Required. The key of the element to return from the `ReverseIterableMap` object.
**Return value**:
* Returns the element associated with the specified key or `undefined` if the key can't be found in the `ReverseIterableMap` object.
A new `ReverseIterableMap` iterator object.
#### Usage
```js
const map = new ReverseIterableMap(['hey', 'beauty'].entries());
map.get(0);
//> 'hey'
### `forEach()`
map.get(1);
//> 'beauty'
The `forEach()` method executes a provided function once per each `[key, value]` pair in the `ReverseIterableMap` object, in insertion order.
map.get(2);
//> undefined
```
### `set()`
#### Syntax
```
map.set(key, value);
map.forEach(callback[, thisArg]);
```

@@ -262,39 +279,38 @@

* **key**: Required. The key of the element to add to the `ReverseIterableMap` object.
* **value**: Required. The value of the element to add to the `ReverseIterableMap` object.
* **callback**: Function to execute for each element.
* **thisArg**: Value to use as `this` when executing `callback`.
**Return value**:
* The `ReverseIterableMap` object.
[`undefined`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined).
#### Usage
```js
const map = new ReverseIterableMap();
map.set('you', 'beauty');
//> map
### `forEachReverse()`
map.set('the-magic-key', 'hey');
//> map
```
The `forEachReverse()` method executes a provided function once per each `[key, value]` pair in the `ReverseIterableMap` object, in reverse-insertion order.
The `set()` method returns a reference to the map object. This makes the set operation chainable.
#### Syntax
```js
const map = new ReverseIterableMap()
.set('key', '… is spelled like tea')
.set('hey', '… somehow ney');
```
map.forEachReverse(callback[, thisArg]);
```
**Parameters**:
* **callback**: Function to execute for each element.
* **thisArg**: Value to use as `this` when executing `callback`.
### `setFirst()`
**Return value**:
The `setFirst()` method functions like `set()` but uses reverse-insertion order.
[`undefined`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined).
### `get()`
#### Syntax
```
map.set(key, value);
map.get(key);
```

@@ -304,8 +320,7 @@

* **key**: Required. The key of the element to add to the `ReverseIterableMap` object.
* **value**: Required. The value of the element to add to the `ReverseIterableMap` object.
* **key**: Required. The key of the element to return from the `ReverseIterableMap` object.
**Return value**:
* The `ReverseIterableMap` object.
* Returns the element associated with the specified key or `undefined` if the key can't be found in the `ReverseIterableMap` object.

@@ -315,11 +330,12 @@ #### Usage

```js
const map = new ReverseIterableMap()
.setFirst('key1', 'was inserted first')
.setFirst('key2', 'was inserted last');
const map = new ReverseIterableMap(['hey', 'beauty'].entries());
map.getFirst();
//> 'was inserted last'
map.get(0);
//> 'hey'
map.getLast();
//> 'was inserted first'
map.get(1);
//> 'beauty'
map.get(2);
//> undefined
```

@@ -329,3 +345,3 @@

### `delete()`
### `has()`

@@ -335,3 +351,3 @@ #### Syntax

```
map.delete(key);
map.has(key);
```

@@ -341,7 +357,7 @@

* **key**: Required. The key of the element to remove from the `ReverseIterableMap` object.
* **key**: Required. The key of the element to test for presence in the `ReverseIterableMap` object.
**Return value**:
* **Boolean**: Returns `true` if an element in the `ReverseIterableMap` object existed and has been removed, or `false` if the element does not exist.
* **Boolean**: Returns `true` if an element with the specified key exists in the `ReverseIterableMap` object; otherwise `false`.

@@ -353,10 +369,10 @@ #### Usage

map.delete(0);
//> true (deletes the key value pair [0, 'hey'])
map.has(0);
//> true
map.delete(1);
//> true (deletes the key value pair [1, 'beauty'])
map.has(1);
//> true
map.delete(2);
//> false (key 2 does not exist in map)
map.has(2);
//> false
```

@@ -366,10 +382,14 @@

### `forEach()`
### `iteratorFor()`
The `forEach()` method executes a provided function once per each `[key, value]` pair in the `ReverseIterableMap` object, in insertion order.
Returns an iterator containing the `[key, value]` pairs for each element in the `ReverseIterableMap` object in insertion order **starting with the pair specified by the `key` parameter**.
This allows starting iteration at a specific element in the map.
An iterator containing the same pairs in reverse-insertion order can be obtained with `iteratorFor().reverseIterator()`.
#### Syntax
```
map.forEach(callback[, thisArg]);
map.iteratorFor(key);
```

@@ -379,40 +399,50 @@

* **callback**: Function to execute for each element.
* **thisArg**: Value to use as `this` when executing `callback`.
* **key**: Required. The key of the element to start iterating from.
**Return value**:
[`undefined`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined).
A new `ReverseIterableMap` iterator object.
#### Usage
```js
const map = new ReverseIterableMap([1, 2, 4].entries());
### `forEachReverse()`
// Iterator, starting at the element with key 1.
const iterator = map.iteratorFor(1);
The `forEachReverse()` method executes a provided function once per each `[key, value]` pair in the `ReverseIterableMap` object, in reverse-insertion order.
iterator.next().value;
//> [1, 2]
#### Syntax
iterator.next().value;
//> [2, 4]
```
map.forEachReverse(callback[, thisArg]);
```
iterator.next().value;
//> undefined
**Parameters**:
// Reverse-iterator, starting at the element with key 1.
const reverseIterator = map.iteratorFor(1).reverseIterator();
* **callback**: Function to execute for each element.
* **thisArg**: Value to use as `this` when executing `callback`.
reverseIterator.next().value;
//> [1, 2]
**Return value**:
reverseIterator.next().value;
//> [0, 1]
[`undefined`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined).
reverseIterator.next().value;
//> undefined
```
### `[Symbol.iterator]()`
### `keys()`
Returns the map iterator function. By default, this is the `entries()` function.
Returns an iterator containing the keys for each element in the `ReverseIterableMap` object in insertion order.
An iterator containing the same keys in reverse-insertion order can be obtained with `keys().reverseIterator()`.
#### Syntax
```
map[Symbol.iterator]();
map.keys();
```

@@ -422,34 +452,14 @@

The map **iterator** function, which is the `entries()` function by default.
A new `ReverseIterableMap` iterator object.
#### Usage
```js
const map = new ReverseIterableMap([1, 2, 4].entries());
const iterator = map[Symbol.iterator]();
### `reverseIterator()`
iterator.next().value;
//> [0, 1]
In theory, following the semantics of `[Symbol.iterator]()`, this should be `[Symbol.reverseIterator]()`. However, as a developer, I cannot define a well-known symbol myself and make use of it. In the future, the a proposal like [The ReverseIterable Interface, by Lee Byron](https://github.com/leebyron/ecmascript-reverse-iterable) might make it’s way into the specification. For the time being, the `reverseIterator()` function serves the same purpose.
iterator.next().value;
//> [1, 2]
iterator.next().value;
//> [2, 4]
iterator.next().value;
//> undefined
```
### `reverse()`
In theory, following the semantics of `[Symbol.iterator]()`, this should be `[Symbol.reverseIterator]()`. However, as a developer, I cannot define a well-known symbol myself and make use of it. In the future, the a proposal like [The ReverseIterable Interface, by Lee Byron](https://github.com/leebyron/ecmascript-reverse-iterable) might make it’s way into the specification. For the time being, the `reverse()` function serves the same purpose.
#### Syntax
```
map.reverse();
map.reverseIterator();
```

@@ -459,3 +469,3 @@

The map **reverse-iterator** function, which is the `entries().reverse()` function by default.
The map **reverse-iterator** function, which is the `entries().reverseIterator()` function by default.

@@ -467,3 +477,3 @@ #### Usage

const reverseIterator = map.reverse();
const reverseIterator = map.reverseIterator();

@@ -485,77 +495,89 @@ reverseIterator.next().value;

### `entries()`
### `set()`
Returns an iterator containing the `[key, value]` pairs for each element in the `ReverseIterableMap` object in insertion order.
An iterator containing the same pairs in reverse-insertion order can be obtained with `entries().reverse()`.
#### Syntax
```
map.entries();
map.set(key, value);
```
**Return value**:
**Parameters**:
A new `ReverseIterableMap` iterator object.
* **key**: Required. The key of the element to add to the `ReverseIterableMap` object.
* **value**: Required. The value of the element to add to the `ReverseIterableMap` object.
**Return value**:
* The `ReverseIterableMap` object.
### `keys()`
#### Usage
Returns an iterator containing the keys for each element in the `ReverseIterableMap` object in insertion order.
```js
const map = new ReverseIterableMap();
An iterator containing the same keys in reverse-insertion order can be obtained with `keys().reverse()`.
map.set('you', 'beauty');
//> map
#### Syntax
map.set('the-magic-key', 'hey');
//> map
```
map.keys();
```
**Return value**:
The `set()` method returns a reference to the map object. This makes the set operation chainable.
A new `ReverseIterableMap` iterator object.
```js
const map = new ReverseIterableMap()
.set('key', '… is spelled like tea')
.set('hey', '… somehow ney');
```
### `values()`
### `setFirst()`
Returns an iterator containing the values for each element in the `ReverseIterableMap` object in insertion order.
The `setFirst()` method functions like `set()` but uses reverse-insertion order.
An iterator containing the same values in reverse-insertion order can be obtained with `values().reverse()`.
#### Syntax
```
map.values();
map.set(key, value);
```
**Parameters**:
* **key**: Required. The key of the element to add to the `ReverseIterableMap` object.
* **value**: Required. The value of the element to add to the `ReverseIterableMap` object.
**Return value**:
A new `ReverseIterableMap` iterator object.
* The `ReverseIterableMap` object.
#### Usage
```js
const map = new ReverseIterableMap()
.setFirst('key1', 'was inserted first')
.setFirst('key2', 'was inserted last');
### `iteratorFor()`
map.values().next().value;
//> 'was inserted last'
Returns an iterator containing the `[key, value]` pairs for each element in the `ReverseIterableMap` object in insertion order **starting with the pair specified by the `key` parameter**.
map.values().reverseIterator().next().value;
//> 'was inserted first'
```
This allows starting iteration at a specific element in the map.
An iterator containing the same pairs in reverse-insertion order can be obtained with `iteratorFor().reverse()`.
### `[Symbol.iterator]()`
Returns the map iterator function. By default, this is the `entries()` function.
#### Syntax
```
map.iteratorFor(key);
map[Symbol.iterator]();
```
**Parameters**:
* **key**: Required. The key of the element to start iterating from.
**Return value**:
A new `ReverseIterableMap` iterator object.
The map **iterator** function, which is the `entries()` function by default.

@@ -567,6 +589,8 @@ #### Usage

// Iterator, starting at the element with key 1.
const iterator = map.iteratorFor(1);
const iterator = map[Symbol.iterator]();
iterator.next().value;
//> [0, 1]
iterator.next().value;
//> [1, 2]

@@ -579,18 +603,24 @@

//> undefined
```
// Reverse-iterator, starting at the element with key 1.
const reverseIterator = map.iteratorFor(1).reverse();
reverseIterator.next().value;
//> [1, 2]
reverseIterator.next().value;
//> [0, 1]
### `values()`
reverseIterator.next().value;
//> undefined
Returns an iterator containing the values for each element in the `ReverseIterableMap` object in insertion order.
An iterator containing the same values in reverse-insertion order can be obtained with `values().reverseIterator()`.
#### Syntax
```
map.values();
```
**Return value**:
A new `ReverseIterableMap` iterator object.
## Why this was implemented

@@ -597,0 +627,0 @@ 

example/example.mjs

Sorry, the diff of this file is not supported yet

src/reverse-iterable-map.mjs

Sorry, the diff of this file is not supported yet

test/tests.mjs

Sorry, the diff of this file is not supported yet