✅ test: update tests & update README

Author: guanghechen

Diff for: packages/huffman/README.md

@@ -105,6 +105,77 @@ A typescript implementation of the **huffman** coding.
   ```
 
 
+## Example
+
+* Compress uri data
+
+  ```typescript
+  const data = { name: 'alice', age: 33, gender: 'female' }
+
+  compress(JSON.stringify(data))
+  // => 'WyIzIiwyMCwiLCIsMTYsIn0iLDM0LCJpIiwzNSwiZyIsMTgsIm4iLDE5LCJsIiwyMSwiciIsNDQsImMiLDkwLCJkIiw5MSwiOiIsMjMsIlwiIiw2LCJlIiwxNCwiYSIsMzAsInsiLDEyNCwiZiIsMTI1LCJtIiw2M10_-BvI)(p7lG1oLi06IEWNvMnvd(l0C'
+
+  decompress('WyIzIiwyMCwiLCIsMTYsIn0iLDM0LCJpIiwzNSwiZyIsMTgsIm4iLDE5LCJsIiwyMSwiciIsNDQsImMiLDkwLCJkIiw5MSwiOiIsMjMsIlwiIiw2LCJlIiwxNCwiYSIsMzAsInsiLDEyNCwiZiIsMTI1LCJtIiw2M10_-BvI)(p7lG1oLi06IEWNvMnvd(l0C')
+  // => '{"name":"alice","age":33,"gender":"female"}'
+
+  function compress(text) {
+    const { encodedData, encodingTable } = huffman.encode(text)
+    const cipherBuffer = huffman.compress(encodedData)
+    const cipherText = base64.encode(cipherBuffer)
+
+    const textEncoder = new TextEncoder('utf-8')
+    const encodingTableText = base64.encode(
+      textEncoder.encode(JSON.stringify(compressEncodingTable(encodingTable))),
+    )
+    const result = (encodingTableText + '-' + cipherText)
+      .replace(/\//g, '(')
+      .replace(/\+/g, ')')
+      .replace(/=/g, '_')
+    return result
+  }
+
+  function decompress(text) {
+    const [encodingTableText, cipherText] = text
+      .replace(/\(/g, '/')
+      .replace(/\)/g, '+')
+      .replace(/_/g, '=')
+      .split('-')
+    const textDecoder = new TextDecoder('utf-8')
+    const encodingTable = decompressEncodingTable(
+      JSON.parse(textDecoder.decode(base64.decode(encodingTableText))),
+    )
+    const tree = huffman.buildHuffmanTree(encodingTable)
+
+    const cipherData = huffman.decompress(base64.decode(cipherText))
+    const plaintext = huffman.decode(cipherData, tree)
+    return plaintext
+  }
+
+  function compressEncodingTable(table) {
+    const entries = Object.entries(table)
+      .map(([value, path]) => {
+        let p = 1
+        for (const x of path) p = (p << 1) | x
+        return [value, p]
+      })
+      .flat()
+    return entries
+  }
+
+  function decompressEncodingTable(entries) {
+    const table = {}
+    for (let i = 0; i < entries.length; i += 2) {
+      const value = entries[i]
+      const p = entries[i + 1]
+      const path = []
+      for (let x = p; x > 1; x >>= 1) path.push(x & 1)
+      table[value] = path.reverse()
+    }
+    return table
+  }
+  ```
+
+
 ## Related
 
 * [Huffman coding | Wikipedia](https://en.wikipedia.org/wiki/Huffman_coding)

Diff for: packages/huffman/__test__/uri-compress.spec.ts

@@ -0,0 +1,81 @@
+import base64 from '@algorithm.ts/base64'
+import { TextDecoder, TextEncoder } from 'util'
+import type { IHuffmanEncodingTable } from '../src'
+import huffman from '../src'
+
+describe('uri-compress', function () {
+  const data = { name: 'alice', age: 33, gender: 'female' }
+
+  test('compress', function () {
+    expect(compress(JSON.stringify(data))).toEqual(
+      'WyIzIiwyMCwiLCIsMTYsIn0iLDM0LCJpIiwzNSwiZyIsMTgsIm4iLDE5LCJsIiwyMSwiciIsNDQsImMiLDkwLCJkIiw5MSwiOiIsMjMsIlwiIiw2LCJlIiwxNCwiYSIsMzAsInsiLDEyNCwiZiIsMTI1LCJtIiw2M10_-BvI)(p7lG1oLi06IEWNvMnvd(l0C',
+    )
+  })
+
+  test('decompress', function () {
+    expect(
+      decompress(
+        'WyIzIiwyMCwiLCIsMTYsIn0iLDM0LCJpIiwzNSwiZyIsMTgsIm4iLDE5LCJsIiwyMSwiciIsNDQsImMiLDkwLCJkIiw5MSwiOiIsMjMsIlwiIiw2LCJlIiwxNCwiYSIsMzAsInsiLDEyNCwiZiIsMTI1LCJtIiw2M10_-BvI)(p7lG1oLi06IEWNvMnvd(l0C',
+      ),
+    ).toEqual('{"name":"alice","age":33,"gender":"female"}')
+  })
+})
+
+function compress(text: string): string {
+  const { encodedData, encodingTable } = huffman.encode(text)
+  const cipherBuffer = huffman.compress(encodedData)
+  const cipherText = base64.encode(cipherBuffer)
+
+  // const textEncoder = new TextEncoder('utf-8')
+  const textEncoder = new TextEncoder()
+  const encodingTableText = base64.encode(
+    textEncoder.encode(JSON.stringify(compressEncodingTable(encodingTable))),
+  )
+  const compressedText = (encodingTableText + '-' + cipherText)
+    .replace(/\//g, '(')
+    .replace(/\+/g, ')')
+    .replace(/=/g, '_')
+  return compressedText
+}
+
+function decompress(compressedText: string): string {
+  const [encodingTableText, cipherText] = compressedText
+    .replace(/\(/g, '/')
+    .replace(/\)/g, '+')
+    .replace(/_/g, '=')
+    .split('-')
+
+  // const textDecoder = new TextDecoder('utf-8')
+  const textDecoder = new TextDecoder()
+  const encodingTable = decompressEncodingTable(
+    JSON.parse(textDecoder.decode(base64.decode(encodingTableText))),
+  )
+  const tree = huffman.buildHuffmanTree(encodingTable)
+
+  const cipherData = huffman.decompress(base64.decode(cipherText))
+  const plaintext = huffman.decode(cipherData, tree)
+  return plaintext
+}
+
+function compressEncodingTable(table: IHuffmanEncodingTable): Array<string | number> {
+  const entries = Object.entries(table)
+    .map(([value, path]) => {
+      let p = 1
+      for (const x of path) p = (p << 1) | x
+      return [value, p] as [string, number]
+    })
+    .flat()
+  return entries
+}
+
+function decompressEncodingTable(entries: Array<string | number>): IHuffmanEncodingTable {
+  const table = {}
+  for (let i = 0; i < entries.length; i += 2) {
+    const value = entries[i] as string
+    const p = entries[i + 1] as number
+    const path = []
+    for (let x = p; x > 1; x >>= 1) path.push(x & 1)
+    table[value] = path.reverse()
+  }
+  return table
+}