Move to manually ESM/CJS dual package

Author: ai

.github/workflows/test.yml

@@ -51,7 +51,7 @@ jobs:
       - name: Install dependencies
         run: pnpm install --frozen-lockfile --ignore-scripts
       - name: Run unit tests
-        run: pnpm unit
+        run: pnpm test
   old:
     runs-on: ubuntu-latest
     strategy:
@@ -77,4 +77,4 @@ jobs:
       - name: Install dependencies
         run: pnpm install --no-frozen-lockfile --ignore-scripts
       - name: Run unit tests
-        run: pnpm unit
+        run: pnpm test

async/index.browser.cjs

@@ -0,0 +1,69 @@
+let random = async bytes => crypto.getRandomValues(new Uint8Array(bytes))
+
+let customAlphabet = (alphabet, defaultSize = 21) => {
+  // First, a bitmask is necessary to generate the ID. The bitmask makes bytes
+  // values closer to the alphabet size. The bitmask calculates the closest
+  // `2^31 - 1` number, which exceeds the alphabet size.
+  // For example, the bitmask for the alphabet size 30 is 31 (00011111).
+  // `Math.clz32` is not used, because it is not available in browsers.
+  let mask = (2 << (Math.log(alphabet.length - 1) / Math.LN2)) - 1
+  // Though, the bitmask solution is not perfect since the bytes exceeding
+  // the alphabet size are refused. Therefore, to reliably generate the ID,
+  // the random bytes redundancy has to be satisfied.
+
+  // Note: every hardware random generator call is performance expensive,
+  // because the system call for entropy collection takes a lot of time.
+  // So, to avoid additional system calls, extra bytes are requested in advance.
+
+  // Next, a step determines how many random bytes to generate.
+  // The number of random bytes gets decided upon the ID size, mask,
+  // alphabet size, and magic number 1.6 (using 1.6 peaks at performance
+  // according to benchmarks).
+
+  // `-~f => Math.ceil(f)` if f is a float
+  // `-~i => i + 1` if i is an integer
+  let step = -~((1.6 * mask * defaultSize) / alphabet.length)
+
+  return async (size = defaultSize) => {
+    let id = ''
+    while (true) {
+      let bytes = crypto.getRandomValues(new Uint8Array(step))
+      // A compact alternative for `for (var i = 0; i < step; i++)`.
+      let i = step | 0
+      while (i--) {
+        // Adding `|| ''` refuses a random byte that exceeds the alphabet size.
+        id += alphabet[bytes[i] & mask] || ''
+        if (id.length === size) return id
+      }
+    }
+  }
+}
+
+let nanoid = async (size = 21) => {
+  let id = ''
+  let bytes = crypto.getRandomValues(new Uint8Array((size |= 0)))
+
+  // A compact alternative for `for (var i = 0; i < step; i++)`.
+  while (size--) {
+    // It is incorrect to use bytes exceeding the alphabet size.
+    // The following mask reduces the random byte in the 0-255 value
+    // range to the 0-63 value range. Therefore, adding hacks, such
+    // as empty string fallback or magic numbers, is unneccessary because
+    // the bitmask trims bytes down to the alphabet size.
+    let byte = bytes[size] & 63
+    if (byte < 36) {
+      // `0-9a-z`
+      id += byte.toString(36)
+    } else if (byte < 62) {
+      // `A-Z`
+      id += (byte - 26).toString(36).toUpperCase()
+    } else if (byte < 63) {
+      id += '_'
+    } else {
+      id += '-'
+    }
+  }
+  return id
+}
+
+module.exports = { nanoid, customAlphabet, random }

async/index.browser.js

@@ -66,4 +66,4 @@ let nanoid = async (size = 21) => {
   return id
 }
 
-module.exports = { nanoid, customAlphabet, random }
+export { nanoid, customAlphabet, random }

async/index.cjs

@@ -0,0 +1,71 @@
+let crypto = require('crypto')
+
+let { urlAlphabet } = require('../url-alphabet/index.cjs')
+
+// `crypto.randomFill()` is a little faster than `crypto.randomBytes()`,
+// because it is possible to use in combination with `Buffer.allocUnsafe()`.
+let random = bytes =>
+  new Promise((resolve, reject) => {
+    // `Buffer.allocUnsafe()` is faster because it doesn’t flush the memory.
+    // Memory flushing is unnecessary since the buffer allocation itself resets
+    // the memory with the new bytes.
+    crypto.randomFill(Buffer.allocUnsafe(bytes), (err, buf) => {
+      if (err) {
+        reject(err)
+      } else {
+        resolve(buf)
+      }
+    })
+  })
+
+let customAlphabet = (alphabet, defaultSize = 21) => {
+  // First, a bitmask is necessary to generate the ID. The bitmask makes bytes
+  // values closer to the alphabet size. The bitmask calculates the closest
+  // `2^31 - 1` number, which exceeds the alphabet size.
+  // For example, the bitmask for the alphabet size 30 is 31 (00011111).
+  let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1
+  // Though, the bitmask solution is not perfect since the bytes exceeding
+  // the alphabet size are refused. Therefore, to reliably generate the ID,
+  // the random bytes redundancy has to be satisfied.
+
+  // Note: every hardware random generator call is performance expensive,
+  // because the system call for entropy collection takes a lot of time.
+  // So, to avoid additional system calls, extra bytes are requested in advance.
+
+  // Next, a step determines how many random bytes to generate.
+  // The number of random bytes gets decided upon the ID size, mask,
+  // alphabet size, and magic number 1.6 (using 1.6 peaks at performance
+  // according to benchmarks).
+  let step = Math.ceil((1.6 * mask * defaultSize) / alphabet.length)
+
+  let tick = (id, size = defaultSize) =>
+    random(step).then(bytes => {
+      // A compact alternative for `for (var i = 0; i < step; i++)`.
+      let i = step
+      while (i--) {
+        // Adding `|| ''` refuses a random byte that exceeds the alphabet size.
+        id += alphabet[bytes[i] & mask] || ''
+        if (id.length >= size) return id
+      }
+      return tick(id, size)
+    })
+
+  return size => tick('', size)
+}
+
+let nanoid = (size = 21) =>
+  random((size |= 0)).then(bytes => {
+    let id = ''
+    // A compact alternative for `for (var i = 0; i < step; i++)`.
+    while (size--) {
+      // It is incorrect to use bytes exceeding the alphabet size.
+      // The following mask reduces the random byte in the 0-255 value
+      // range to the 0-63 value range. Therefore, adding hacks, such
+      // as empty string fallback or magic numbers, is unneccessary because
+      // the bitmask trims bytes down to the alphabet size.
+      id += urlAlphabet[bytes[size] & 63]
+    }
+    return id
+  })
+
+module.exports = { nanoid, customAlphabet, random }

async/index.js

@@ -1,6 +1,6 @@
-let crypto = require('crypto')
+import crypto from 'crypto'
 
-let { urlAlphabet } = require('../url-alphabet')
+import { urlAlphabet } from '../url-alphabet/index.js'
 
 // `crypto.randomFill()` is a little faster than `crypto.randomBytes()`,
 // because it is possible to use in combination with `Buffer.allocUnsafe()`.
@@ -68,4 +68,4 @@ let nanoid = (size = 21) =>
     return id
   })
 
-module.exports = { nanoid, customAlphabet, random }
+export { nanoid, customAlphabet, random }

async/index.native.js

@@ -1,6 +1,6 @@
-let { getRandomBytesAsync } = require('expo-random')
+import { getRandomBytesAsync } from 'expo-random'
 
-let { urlAlphabet } = require('../url-alphabet')
+import { urlAlphabet } from '../url-alphabet/index.js'
 
 let random = getRandomBytesAsync
 
@@ -54,4 +54,4 @@ let nanoid = (size = 21) =>
     return id
   })
 
-module.exports = { nanoid, customAlphabet, random }
+export { nanoid, customAlphabet, random }

async/package.json

@@ -0,0 +1,12 @@
+{
+  "type": "module",
+  "main": "index.cjs",
+  "module": "index.js",
+  "react-native": {
+    "./index.js": "./index.native.js"
+  },
+  "browser": {
+    "./index.js": "./index.browser.js",
+    "./index.cjs": "./index.browser.cjs"
+  }
+}

index.browser.cjs

@@ -0,0 +1,72 @@
+// This file replaces `index.js` in bundlers like webpack or Rollup,
+// according to `browser` config in `package.json`.
+
+let { urlAlphabet } = require('./url-alphabet/index.cjs')
+
+let random = bytes => crypto.getRandomValues(new Uint8Array(bytes))
+
+let customRandom = (alphabet, defaultSize, getRandom) => {
+  // First, a bitmask is necessary to generate the ID. The bitmask makes bytes
+  // values closer to the alphabet size. The bitmask calculates the closest
+  // `2^31 - 1` number, which exceeds the alphabet size.
+  // For example, the bitmask for the alphabet size 30 is 31 (00011111).
+  // `Math.clz32` is not used, because it is not available in browsers.
+  let mask = (2 << (Math.log(alphabet.length - 1) / Math.LN2)) - 1
+  // Though, the bitmask solution is not perfect since the bytes exceeding
+  // the alphabet size are refused. Therefore, to reliably generate the ID,
+  // the random bytes redundancy has to be satisfied.
+
+  // Note: every hardware random generator call is performance expensive,
+  // because the system call for entropy collection takes a lot of time.
+  // So, to avoid additional system calls, extra bytes are requested in advance.
+
+  // Next, a step determines how many random bytes to generate.
+  // The number of random bytes gets decided upon the ID size, mask,
+  // alphabet size, and magic number 1.6 (using 1.6 peaks at performance
+  // according to benchmarks).
+
+  // `-~f => Math.ceil(f)` if f is a float
+  // `-~i => i + 1` if i is an integer
+  let step = -~((1.6 * mask * defaultSize) / alphabet.length)
+
+  return (size = defaultSize) => {
+    let id = ''
+    while (true) {
+      let bytes = getRandom(step)
+      // A compact alternative for `for (var i = 0; i < step; i++)`.
+      let j = step | 0
+      while (j--) {
+        // Adding `|| ''` refuses a random byte that exceeds the alphabet size.
+        id += alphabet[bytes[j] & mask] || ''
+        if (id.length === size) return id
+      }
+    }
+  }
+}
+
+let customAlphabet = (alphabet, size = 21) =>
+  customRandom(alphabet, size, random)
+
+let nanoid = (size = 21) =>
+  crypto.getRandomValues(new Uint8Array(size)).reduce((id, byte) => {
+    // It is incorrect to use bytes exceeding the alphabet size.
+    // The following mask reduces the random byte in the 0-255 value
+    // range to the 0-63 value range. Therefore, adding hacks, such
+    // as empty string fallback or magic numbers, is unneccessary because
+    // the bitmask trims bytes down to the alphabet size.
+    byte &= 63
+    if (byte < 36) {
+      // `0-9a-z`
+      id += byte.toString(36)
+    } else if (byte < 62) {
+      // `A-Z`
+      id += (byte - 26).toString(36).toUpperCase()
+    } else if (byte > 62) {
+      id += '-'
+    } else {
+      id += '_'
+    }
+    return id
+  }, '')
+
+module.exports = { nanoid, customAlphabet, customRandom, urlAlphabet, random }

index.browser.js

@@ -1,7 +1,7 @@
 // This file replaces `index.js` in bundlers like webpack or Rollup,
 // according to `browser` config in `package.json`.
 
-let { urlAlphabet } = require('./url-alphabet')
+import { urlAlphabet } from './url-alphabet/index.js'
 
 let random = bytes => crypto.getRandomValues(new Uint8Array(bytes))
 
@@ -69,4 +69,4 @@ let nanoid = (size = 21) =>
     return id
   }, '')
 
-module.exports = { nanoid, customAlphabet, customRandom, urlAlphabet, random }
+export { nanoid, customAlphabet, customRandom, urlAlphabet, random }

index.cjs

@@ -0,0 +1,85 @@
+let crypto = require('crypto')
+
+let { urlAlphabet } = require('./url-alphabet/index.cjs')
+
+// It is best to make fewer, larger requests to the crypto module to
+// avoid system call overhead. So, random numbers are generated in a
+// pool. The pool is a Buffer that is larger than the initial random
+// request size by this multiplier. The pool is enlarged if subsequent
+// requests exceed the maximum buffer size.
+const POOL_SIZE_MULTIPLIER = 128
+let pool, poolOffset
+
+let fillPool = bytes => {
+  if (!pool || pool.length < bytes) {
+    pool = Buffer.allocUnsafe(bytes * POOL_SIZE_MULTIPLIER)
+    crypto.randomFillSync(pool)
+    poolOffset = 0
+  } else if (poolOffset + bytes > pool.length) {
+    crypto.randomFillSync(pool)
+    poolOffset = 0
+  }
+  poolOffset += bytes
+}
+
+let random = bytes => {
+  // `|=` convert `bytes` to number to prevent `valueOf` abusing and pool pollution
+  fillPool((bytes |= 0))
+  return pool.subarray(poolOffset - bytes, poolOffset)
+}
+
+let customRandom = (alphabet, defaultSize, getRandom) => {
+  // First, a bitmask is necessary to generate the ID. The bitmask makes bytes
+  // values closer to the alphabet size. The bitmask calculates the closest
+  // `2^31 - 1` number, which exceeds the alphabet size.
+  // For example, the bitmask for the alphabet size 30 is 31 (00011111).
+  let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1
+  // Though, the bitmask solution is not perfect since the bytes exceeding
+  // the alphabet size are refused. Therefore, to reliably generate the ID,
+  // the random bytes redundancy has to be satisfied.
+
+  // Note: every hardware random generator call is performance expensive,
+  // because the system call for entropy collection takes a lot of time.
+  // So, to avoid additional system calls, extra bytes are requested in advance.
+
+  // Next, a step determines how many random bytes to generate.
+  // The number of random bytes gets decided upon the ID size, mask,
+  // alphabet size, and magic number 1.6 (using 1.6 peaks at performance
+  // according to benchmarks).
+  let step = Math.ceil((1.6 * mask * defaultSize) / alphabet.length)
+
+  return (size = defaultSize) => {
+    let id = ''
+    while (true) {
+      let bytes = getRandom(step)
+      // A compact alternative for `for (let i = 0; i < step; i++)`.
+      let i = step
+      while (i--) {
+        // Adding `|| ''` refuses a random byte that exceeds the alphabet size.
+        id += alphabet[bytes[i] & mask] || ''
+        if (id.length === size) return id
+      }
+    }
+  }
+}
+
+let customAlphabet = (alphabet, size = 21) =>
+  customRandom(alphabet, size, random)
+
+let nanoid = (size = 21) => {
+  // `|=` convert `size` to number to prevent `valueOf` abusing and pool pollution
+  fillPool((size |= 0))
+  let id = ''
+  // We are reading directly from the random pool to avoid creating new array
+  for (let i = poolOffset - size; i < poolOffset; i++) {
+    // It is incorrect to use bytes exceeding the alphabet size.
+    // The following mask reduces the random byte in the 0-255 value
+    // range to the 0-63 value range. Therefore, adding hacks, such
+    // as empty string fallback or magic numbers, is unneccessary because
+    // the bitmask trims bytes down to the alphabet size.
+    id += urlAlphabet[pool[i] & 63]
+  }
+  return id
+}
+
+module.exports = { nanoid, customAlphabet, customRandom, urlAlphabet, random }