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1## FPJS
2
3A Functional tool set for my own learning FP style.
4Implemented by referring many other's source.
5
6Introduced the beginning of this repository in [Medium post](https://medium.com/@andrwj/either-implementation-that-is-throwable-and-catchable-5b0015f4b6e3)
7
8
9## Installation
10
11`npm install @andrwj/fp`
12
13
14## Usage (Not fully documented yet)
15* In command line:
16`node -r esm --harmony ./index.js`
17
18* In ReactJS/VueJS/RunJS: `import * as FP from '@andrwj/fp'`
19
20## Either
21### static methods
22* `Either.of(value, f)` - `f` is optional
23* `Either.fromNullable(value)`
24* `Either.filter(f, condition_f=truth)` - `condition_f` is optional
25* `Either.right(value)`
26* `Either.left(value)`
27* `Either.done(value)`
28* `Either.doneIf(f, value)`
29* `Either.throw(value)` - this throws `Right(value)` not Error instnace !!! and then only .`catch()` handle the passed `Right`
30* `Either.throwIf(f, value)`
31* `Either.try(f)`
32
33### instance methods for Right
34 * `.inspect(f)`
35 * `.try(f)`
36 * `.throw()`
37 * `.tap(f=console.log)`
38 * `.take(f)`
39 * `.map(f)`
40 * `.chain(f)`
41 * `.filter(f)`
42 * `.fold(_right, _left)`
43 * `.done()`
44 * `.doneIf(f)`
45 * `.throwIf(f, value)`
46 * `.apply( instance_of_Either )`
47
48### instance methods for Left
49 * `.inspect(f)`
50 * `.tap(f=console.log)`
51 * `.take(f)`
52 * `.fold(_right, _left)`
53
54### NOTE
55 * All methods work for Right only.
56 * Only Right can `.throw()` or `.done()`
57 * Basically Left will skip most methods except `inspect, tap, take, fold`
58 * `throw()` does not throw Error. It is deliver of `Right` to `.catch()`.
59 * If you `throw()`, execution flow goes until find `.catch()`
60 * If you `done()`, execution flow goes until find `.fold()` or `.take()`
61 * If there is no exception in `try(f)`, return value will be of **Right**. If Exception occurs, then the return value will be of **Left**.
62 * If you do not want to get **Unhandled Promise Rejection Error** in `.try(f)`, you HAVE TO deal with its logic of `f` yourself. The unhandled error is not because of `.try()` but because of your misunderstanding of Promise chain.
63
64## Fromise (Experimental; Promimse + Either)
65 * `Fromise.resolve (expr)`
66 * `Fromise.reject (expr)`
67 * `Fromise.isPromise (value)`
68 * `.pipe (...funcs)`
69 * `.if (f_condition, if_true, if_false)`
70 * `.tap (f)`
71 * `.either (f)`
72 * `.map (f)`
73 * `.fold (f, g)`
74 * `.chain (f)`
75
76## High Order Functions (Not fully documented yet)
77 * `run(v, f1, f2, f3, ... ) : value`
78 * `pipe(f1, f2, f3, ...) : function`
79
80## Utilities (Not fully documented yet)
81 * `isFunction (v)` - return true if `v` is function
82 * `isFalsy (v)` - true if `v` is one of `undefined`, `NaN`, `null`
83 * `isFalse (v)` - true if `v` is one of `undefined`, `NaN`, `null`, `0`, `""`
84 * `identity (v)` - returns `v`, always.
85
86## Changes
87
88### `v0.2.4` Published compiled source by Babel7
89
90### `v0.2.0` break changes to version of `0.1.*`
91* changed arguments order and way: `Either.of(f, value)` ➡ `Either.of(value, f)` - if `f` is not given, it just returns `Right(value)`. Otherwise, it returns `Right(value)` or `Left(value)` depends on the boolean result of `f(value)`
92* changed arguments: `.catch(f, condition_f)` ➡ `.catch(f)` - if `f` is not given, it returns the instance of thrown from `.throw()`. Otherwise it returns `.map(f)`
93* added: `.of(value, f)` - same as `Either.of(value, f)`
94* added: `isNotFalsy(v) : boolean `