size: add utf16.browser impl

Author: ChALkeR

package.json

@@ -124,6 +124,7 @@
     "/single-byte.node.js",
     "/utf16.js",
     "/utf16.d.ts",
+    "/utf16.browser.js",
     "/utf16.native.js",
     "/utf16.node.js",
     "/utf8.js",
@@ -205,6 +206,7 @@
       "types": "./utf16.d.ts",
       "node": "./utf16.node.js",
       "react-native": "./utf16.native.js",
+      "browser": "./utf16.browser.js",
       "default": "./utf16.js"
     },
     "./utf8.js": {
@@ -222,6 +224,7 @@
     }
   },
   "browser": {
+    "./utf16.js": "./utf16.browser.js",
     "./fallback/utf8.auto.js": "./fallback/utf8.auto.browser.js"
   },
   "react-native": {

utf16.browser.js

@@ -0,0 +1,48 @@
+// We trust browsers to always have correct TextDecoder / TextEncoder for UTF-16 with ignoreBOM without streaming
+
+import { encode as encodeJS } from './fallback/utf16.js'
+import { isLE, E_STRING, E_STRICT_UNICODE } from './fallback/_utils.js'
+
+const ignoreBOM = true
+const decoderFatalLE = new TextDecoder('utf-16le', { ignoreBOM, fatal: true })
+const decoderLooseLE = new TextDecoder('utf-16le', { ignoreBOM })
+const decoderFatalBE = new TextDecoder('utf-16be', { ignoreBOM, fatal: true })
+const decoderLooseBE = new TextDecoder('utf-16be', { ignoreBOM })
+const decoderFatal16 = isLE ? decoderFatalLE : decoderFatalBE
+const decoderLoose16 = isLE ? decoderLooseLE : decoderLooseBE
+const { isWellFormed } = String.prototype
+
+function encode(str, loose, format) {
+  if (typeof str !== 'string') throw new TypeError(E_STRING)
+  if (format !== 'uint16' && format !== 'uint8-le' && format !== 'uint8-be') {
+    throw new TypeError('Unknown format')
+  }
+
+  if (!loose && isWellFormed && !isWellFormed.call(str)) throw new TypeError(E_STRICT_UNICODE)
+  const shouldSwap = (isLE && format === 'uint8-be') || (!isLE && format === 'uint8-le')
+  const u16 = encodeJS(str, loose, !loose && isWellFormed, shouldSwap)
+  return format === 'uint16' ? u16 : new Uint8Array(u16.buffer, u16.byteOffset, u16.byteLength)
+}
+
+function decode(input, loose, format) {
+  switch (format) {
+    case 'uint16':
+      if (!(input instanceof Uint16Array)) throw new TypeError('Expected an Uint16Array')
+      return loose ? decoderLoose16.decode(input) : decoderFatal16.decode(input)
+    case 'uint8-le':
+      if (!(input instanceof Uint8Array)) throw new TypeError('Expected an Uint8Array')
+      if (input.byteLength % 2 !== 0) throw new TypeError('Expected even number of bytes')
+      return loose ? decoderLooseLE.decode(input) : decoderFatalLE.decode(input)
+    case 'uint8-be':
+      if (!(input instanceof Uint8Array)) throw new TypeError('Expected an Uint8Array')
+      if (input.byteLength % 2 !== 0) throw new TypeError('Expected even number of bytes')
+      return loose ? decoderLooseBE.decode(input) : decoderFatalBE.decode(input)
+  }
+
+  throw new TypeError('Unknown format')
+}
+
+export const utf16fromString = (str, format = 'uint16') => encode(str, false, format)
+export const utf16fromStringLoose = (str, format = 'uint16') => encode(str, true, format)
+export const utf16toString = (arr, format = 'uint16') => decode(arr, false, format)
+export const utf16toStringLoose = (arr, format = 'uint16') => decode(arr, true, format)