used "arbitrary module namespace identifier names" in esm codgen

lib/compile/codegen/code.ts

@@ -158,8 +158,8 @@ export function getProperty(key: Code | string | number): Code {
 
 //Does best effort to format the name properly
 export function getEsmExportName(key: Code | string | number): Code {
-  if (typeof key == "string" && IDENTIFIER.test(key)) {
-    return new _Code(`${key}`)
+  if (typeof key == "string") {
+    return IDENTIFIER.test(key) ? new _Code(`${key}`) : _`${key}`
   }
   throw new Error(`CodeGen: invalid export name: ${key}, use explicit $id name mapping`)
 }

lib/standalone/index.ts

@@ -32,7 +32,7 @@ function standaloneCode(
     const vCode = validateCode(usedValues, source)
     if (ajv.opts.code.esm) {
       // Always do named export as `validate` rather than the variable `n` which is `validateXX` for known export value
-      return `"use strict";${_n}export const validate = ${n};${_n}export default ${n};${_n}${vCode}`
+      return `"use strict";${_n}export {${n} as validate,${_n}${n} as default};${_n}${vCode}`
     }
     return `"use strict";${_n}module.exports = ${n};${_n}module.exports.default = ${n};${_n}${vCode}`
   }
@@ -48,9 +48,9 @@ function standaloneCode(
       if (v) {
         const vCode = validateCode(usedValues, v.source)
         const exportSyntax = ajv.opts.code.esm
-          ? _`export const ${getEsmExportName(name)}`
-          : _`exports${getProperty(name)}`
-        code = _`${code}${_n}${exportSyntax} = ${v.source?.validateName};${_n}${vCode}`
+          ? _`export { ${v.source?.validateName} as ${getEsmExportName(name)} };`
+          : _`exports${getProperty(name)} = ${v.source?.validateName};`
+        code = _`${code}${_n}${exportSyntax}${_n}${vCode}`
       }
     }
     return `${code}`

spec/standalone.spec.ts

@@ -9,9 +9,9 @@ import assert = require("assert")
 
 function testExportTypeEsm(moduleCode: string, singleExport: boolean) {
   //Must have
-  assert.strictEqual(moduleCode.includes("export const"), true)
+  assert.strictEqual(moduleCode.includes("export {"), true)
   if (singleExport) {
-    assert.strictEqual(moduleCode.includes("export default"), true)
+    assert.strictEqual(moduleCode.includes("as default"), true)
   }
   //Must not have
   assert.strictEqual(moduleCode.includes("module.exports"), false)