https://github.com/grantila/binmap
Ordered Map (ES Map compatible)
https://github.com/grantila/binmap
Last synced: 6 months ago
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Ordered Map (ES Map compatible)
- Host: GitHub
- URL: https://github.com/grantila/binmap
- Owner: grantila
- License: mit
- Created: 2018-06-19T13:52:06.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2020-05-30T19:53:49.000Z (over 5 years ago)
- Last Synced: 2024-12-17T01:34:22.051Z (10 months ago)
- Language: TypeScript
- Size: 43.9 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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# binmap
`binmap` is a `Map` implementation compatible to the [Built-in Map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) but guaranteeing the keys to be ordered.
The constructor has an optional options object and the class has a member function `between` for iterating between two boundary keys.
`BinMap` instances are convertible to and from built-in Maps and Arrays (of sub-arrays).
# Functions
* [Constructor](#constructor)
* [between](#between)
## Constructor
The constructor works like the built-in Map in that it can optionally take an iterable of key-value pairs (as individual arrays), but can also have an extra optional options object which can contain a comparison function `cmp` with the same semantics as the custom [`sort` comparator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort).
```ts
import BinMap from 'binmap'
// Custom comparator
const cmp = ( a, b ) => a.length - b.length;
const bm1 = new BinMap( { cmp } );
// or
const bm2 = new BinMap( [ [ 'key1', 'value1' ], ... ], { cmp } );
```
## betwen
`between( { ... } )` returns an IterableIterator between two boundary keys. The options object can contain:
- **Either** an `lt` (less than) **or** an `le` (less than or equal to).
- **Either** a `gt` (greater than) **or** a `ge` (greater than or equal to).
- `reverse` being a boolean (defaults to `false`), which if `true` returns an iterator from the end to the beginning of the span.
There are two magic values for `lt`, `le`, `gt` and `ge` which is `BinMap.min` and `BinMap.max` which represents the lowest/highest possible values. These are also the default, so an empty `between( { } )` (or just `between( )`) iterates the whole map.
```ts
import BinMap from 'binmap'
const bm = new BinMap( [
[ "a", 1 ],
[ "b", 2 ],
[ "c", 3 ],
[ "d", 4 ],
] );
Array.from( bm.between( { gt: 'b' } ) )
// -> [ [ "c", 3 ], [ "d", 4 ] ]
Array.from( bm.between( { gt: 'b', reverse: true } ) )
// -> [ [ "d", 4 ], [ "c", 3 ] ]
```
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