New Feature: export lenses for options management

Author: gcanti

README.md

@@ -118,6 +118,24 @@ export const defaultOptions: Options = {
 }
 ```
 
+## Options management
+
+Example
+
+```ts
+import { lenses, defaultOptions } from 'fp-ts-codegen/lib/ast'
+
+lenses.tagName.set('tag')(defaultOptions)
+/*
+{
+  tagName: 'tag',
+  foldName: 'fold',
+  matcheeName: 'fa',
+  ...
+}
+*/
+```
+
 # Modules
 
 - `ast` module: internal model -> TypeScript AST

package-lock.json

@@ -30,6 +30,7 @@
   "homepage": "https://github.com/gcanti/fp-ts-codegen",
   "dependencies": {
     "fp-ts": "^1.13.0",
+    "monocle-ts": "^1.5.3",
     "parser-ts": "^0.5.1",
     "typescript": "^3.2.4"
   },

package.json

@@ -3,6 +3,7 @@ import { Reader, reader, ask } from 'fp-ts/lib/Reader'
 import { array, empty } from 'fp-ts/lib/Array'
 import * as ts from 'typescript'
 import * as M from './model'
+import { Lens } from 'monocle-ts'
 
 export interface Options {
   /** the name of the field used as tag */
@@ -19,6 +20,14 @@ export const defaultOptions: Options = {
   matcheeName: 'fa'
 }
 
+const getLens = Lens.fromProp<Options>()
+
+export const lenses: { [K in keyof Options]: Lens<Options, Options[K]> } = {
+  tagName: getLens('tagName'),
+  foldName: getLens('foldName'),
+  matcheeName: getLens('matcheeName')
+}
+
 export interface AST<A> extends Reader<Options, A> {}
 
 const getMemberName = (m: M.Member, position: number): string => {

src/ast.ts

@@ -1,7 +1,7 @@
 import * as assert from 'assert'
 import * as P from '../src/printer'
 import * as H from './helpers'
-import { Options, defaultOptions } from '../src/ast'
+import { Options, defaultOptions, lenses } from '../src/ast'
 
 const assertEqual = <A, B>(f: (a: A) => P.Printer<B>, a: A, expected: B, options: Options = defaultOptions) => {
   const actual = f(a).run(options)
@@ -220,7 +220,7 @@ export function user(name: string, surname: string): User { return { type: "User
       it('should handle custom tag names', () => {
         const printer = P.print
         assert.strictEqual(
-          printer(H.Option, { tagName: 'tag', foldName: 'fold', matcheeName: 'fa' }),
+          printer(H.Option, lenses.tagName.set('tag')(defaultOptions)),
           `export type Option<A> = {
     readonly tag: "None";
 } | {
@@ -258,7 +258,7 @@ export function foldL<A, R>(fa: Option<A>, onNone: () => R, onSome: (value0: A)
     case "Some": return onSome(fa.value0);
 } }`
           ],
-          { tagName: 'type', foldName: 'match', matcheeName: 'fa' }
+          lenses.foldName.set('match')(defaultOptions)
         )
       })
 
@@ -276,7 +276,7 @@ export function foldL<A, R>(fa: Option<A>, onNone: () => R, onSome: (value0: A)
     case "Some": return onSome(input.value0);
 } }`
           ],
-          { tagName: 'type', foldName: 'fold', matcheeName: 'input' }
+          lenses.matcheeName.set('input')(defaultOptions)
         )
       })
     })