From 65e50601f2561ae18a49c20461567d8ddf6d2f89 Mon Sep 17 00:00:00 2001
From: Anton Golub <antongolub@antongolub.com>
Date: Fri, 22 Sep 2023 15:35:35 +0300
Subject: [PATCH] feat: bring low-level filter

---
 README.md                 |  3 ++-
 src/main/ts/index.ts      | 17 +++++++++++------
 src/main/ts/interface.ts  |  5 ++++-
 src/test/ts/index.test.ts |  6 +++++-
 4 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index fe17ff1..1c8049e 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,8 @@ const tower = createTower({
   committerName:  'Foo Bar',      // Username and email to sign annotaged git tags
   committerEmail: 'foo@bar.baz',  // Defaults to Semrel Extra Bot <semrel-extra-bot@hotmail.com>
   format:         v => v + '',    // Opt value formatter. Defaults to JSON.stringify
-  parse:          v => v          // Opt parser. Defaults to JSON.parse
+  parse:          v => v,         // Opt parser. Defaults to JSON.parse
+  filter:         v => v % 2      // Opt low level filter (applied before parse). Defaults to () => true
 })
 
 const id: string = 'some@tag'
diff --git a/src/main/ts/index.ts b/src/main/ts/index.ts
index 1e6f61b..463dca2 100644
--- a/src/main/ts/index.ts
+++ b/src/main/ts/index.ts
@@ -1,5 +1,5 @@
 import {readTags, deleteTag, pushTags} from './git'
-import {TTagEntry, TTower, TTowerFactory, TTowerOpts} from './interface'
+import {TFilter, TTagEntry, TTower, TTowerFactory, TTowerOpts} from './interface'
 
 export const createTower: TTowerFactory = (opts: TTowerOpts): TTower => ({
   async create(tag, data){
@@ -8,14 +8,18 @@ export const createTower: TTowerFactory = (opts: TTowerOpts): TTower => ({
   },
   // eslint-disable-next-line @typescript-eslint/ban-ts-comment
   // @ts-ignore
-  async read(id?: string) {
+  async read(id?: string | TFilter) {
     const parser = opts.parse || parse
-    const entries: TTagEntry[] = (await readTags(opts)).map(({tag: id, body}) => ({id, data: parser(body)}))
-    if (id === undefined) {
-      return entries
+    const predicate = typeof id === 'function' ? id : (opts.filter || filter)
+    const entries: TTagEntry[] = (await readTags(opts))
+      .filter(predicate)
+      .map(({tag: id, body}) => ({id, data: parser(body)}))
+
+    if (typeof id === 'string') {
+      return entries.find(({id: _id}) => _id === id) || null
     }
 
-    return entries.find(({id: _id}) => _id === id) || null
+    return entries
   },
   async delete(tag) {
     await deleteTag({...opts, tag})
@@ -26,6 +30,7 @@ export const createTower: TTowerFactory = (opts: TTowerOpts): TTower => ({
   }
 })
 
+const filter = () => true
 const format = JSON.stringify
 const parse = (value: any): TTagEntry['data'] => {
   try {
diff --git a/src/main/ts/interface.ts b/src/main/ts/interface.ts
index 9567012..af1ddab 100644
--- a/src/main/ts/interface.ts
+++ b/src/main/ts/interface.ts
@@ -4,10 +4,12 @@ export type TTagEntry = {
   data: any
 }
 
+export type TFilter = (v: {tag: string, body: string}) => boolean
+
 export type TTower = {
   create(id: string, data: TTagEntry['data']): Promise<void>
   read(id: string): Promise<TTagEntry | null>
-  read(): Promise<TTagEntry[]>
+  read(fn?: TFilter): Promise<TTagEntry[]>
   update(id: string, data: TTagEntry['data']): Promise<void>
   delete(id: string): Promise<void>
 }
@@ -22,6 +24,7 @@ export type TTowerOpts = {
   committerEmail?: string
   parse?: (v: string) => any
   format?: (v: any) => string
+  filter?: TFilter
 }
 
 export type TAnnotatedTag = {
diff --git a/src/test/ts/index.test.ts b/src/test/ts/index.test.ts
index 82389ac..3dab378 100644
--- a/src/test/ts/index.test.ts
+++ b/src/test/ts/index.test.ts
@@ -41,7 +41,7 @@ describe('tagTower', () => {
     assert.equal(await tower.read(id), null)
   })
 
-  it('supports custom parse/format', async () => {
+  it('supports custom parse, format & filter', async () => {
     const cwd = path.resolve(temp, 'custom-format')
     await fs.mkdir(cwd, { recursive: true })
     await exec('git', ['init', '--bare'], {cwd})
@@ -55,6 +55,10 @@ describe('tagTower', () => {
     })
 
     await tower.create('foo', 'bar')
+    await tower.create('baz', 'qux')
     assert.equal((await tower.read('foo'))?.data, '++bar++')
+
+    const filtered = await tower.read(({tag}) => tag === 'foo')
+    assert.deepEqual(filtered, [{id: 'foo', data: '++bar++'}])
   })
 })