add ponyfill

Author: wangcheng

build.js

@@ -1,7 +1,7 @@
 import * as esbuild from 'esbuild';
 import * as fs from 'fs';
 
-const out = esbuild.buildSync({
+esbuild.buildSync({
   entryPoints: ['src/polyfill.js'],
   bundle: true,
   format: 'esm',
@@ -21,5 +21,22 @@ const out = esbuild.buildSync({
 // confirm it imports
 await import('./text.min.js');
 
-const stat = fs.statSync('text.min.js');
-console.info(`text.min.js: ${stat.size}`);
+const polyfillStat = fs.statSync('text.min.js');
+console.info(`text.min.js: ${polyfillStat.size}`);
+
+esbuild.buildSync({
+  entryPoints: ['src/ponyfill.js'],
+  bundle: true,
+  format: 'cjs',
+  platform: 'neutral',
+  sourcemap: 'external',
+  outfile: './package/ponyfill.js',
+  target: 'es5',
+  minify: true,
+});
+
+// confirm it imports
+await import('./package/ponyfill.js');
+
+const ponyfillStat = fs.statSync('ponyfill.js');
+console.info(`ponyfill.js: ${ponyfillStat.size}`);

ponyfill.js

@@ -0,0 +1,2 @@
+export { FastTextEncoder } from './o-encoder.js';
+export { FastTextDecoder } from './o-decoder.js';