feat: add option to generate ESM exports instead of CJS (ajv-validato…

…r#1523)

- Renamed exportEsm to esm
- Extracted common code
- Changed invalid export names to rather throw an error

docs/guide/environments.md

@@ -100,7 +100,7 @@ The default configuration of AJV is to generate code in ES6 with Common JS (CJS)
 the ES Modules(ESM) flag.
 
 ```javascript
-const ajv = new Ajv({code: {exportEsm: true}})
+const ajv = new Ajv({code: {esm: true}})
 ```
 
 ## Other JavaScript environments

docs/options.md

@@ -65,7 +65,7 @@ const defaultOptions = {
   code: {
     // NEW
     es5: false,
-    exportEsm: false,
+    esm: false,
     lines: false,
     source: false,
     process: undefined, // (code: string) => string
@@ -348,7 +348,7 @@ Code generation options:
 ```typescript
 type CodeOptions = {
   es5?: boolean // to generate es5 code - by default code is es6, with "for-of" loops, "let" and "const"
-  exportEsm?: boolean // how functions should be exported - by default CJS is used, so the validate function(s) 
+  esm?: boolean // how functions should be exported - by default CJS is used, so the validate function(s) 
   // file can be `required`. Set this value to true to export the validate function(s) as ES Modules, enabling 
   // bunlers to do their job.
   lines?: boolean // add line-breaks to code - to simplify debugging of generated functions

lib/compile/codegen/code.ts

@@ -160,12 +160,7 @@ export function getEsmExportName(key: Code | string | number): Code {
   if (typeof key == "string" && IDENTIFIER.test(key)) {
     return new _Code(`${key}`)
   }
-  const name = key.toString()
-  let newName = name.replace(/[^\w$_]|[\s]/gi, "_")
-  if (/^[0-9]/.test(name)) {
-    newName = "_" + newName
-  }
-  return new _Code(`${newName}`)
+  throw new Error(`CodeGen: invalid export name: ${key}, use explicit $id name mapping`)
 }
 
 export function regexpCode(rx: RegExp): Code {

lib/core.ts

@@ -140,7 +140,7 @@ export interface CurrentOptions {
 
 export interface CodeOptions {
   es5?: boolean
-  exportEsm?: boolean
+  esm?: boolean
   lines?: boolean
   optimize?: boolean | number
   formats?: Code // code to require (or construct) map of available formats - for standalone code

lib/standalone/index.ts

@@ -30,7 +30,7 @@ function standaloneCode(
     const usedValues: UsedScopeValues = {}
     const n = source?.validateName
     const vCode = validateCode(usedValues, source)
-    if (ajv.opts.code.exportEsm) {
+    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}${vCode}`
     }
@@ -47,15 +47,10 @@ function standaloneCode(
       const v = getValidateFunc(schemas[name] as T)
       if (v) {
         const vCode = validateCode(usedValues, v.source)
-        if (ajv.opts.code.exportEsm) {
-          code = _`${code}${_n}export const ${getEsmExportName(name)} = ${
-            v.source?.validateName
-          };${_n}${vCode}`
-        } else {
-          code = _`${code}${_n}exports${getProperty(name)} = ${
-            v.source?.validateName
-          };${_n}${vCode}`
-        }
+        const exportSyntax = ajv.opts.code.esm
+          ? _`export const ${getEsmExportName(name)}`
+          : _`exports${getProperty(name)}`
+        code = _`${code}${_n}${exportSyntax} = ${v.source?.validateName};${_n}${vCode}`
       }
     }
     return `${code}`

spec/standalone.spec.ts

@@ -57,7 +57,7 @@ describe("standalone code generation", () => {
       })
 
       it("should generate module code with named export - ESM", () => {
-        ajv = new _Ajv({code: {source: true, exportEsm: true}})
+        ajv = new _Ajv({code: {source: true, esm: true}})
         ajv.addSchema(numSchema)
         ajv.addSchema(strSchema)
         const moduleCode = standaloneCode(ajv, {
@@ -85,17 +85,24 @@ describe("standalone code generation", () => {
       })
 
       it("should generate module code with all exports - ESM", () => {
-        ajv = new _Ajv({code: {source: true, exportEsm: true}})
+        ajv = new _Ajv({code: {source: true, esm: true}})
         ajv.addSchema(numSchema)
         ajv.addSchema(strSchema)
-        const moduleCode = standaloneCode(ajv)
-        testExportTypeEsm(moduleCode, false)
-        const m = importFromStringSync(moduleCode)
-        assert.strictEqual(Object.keys(m).length, 2)
-        testExports({
-          validateNumber: m.https___example_com_number_json,
-          validateString: m.https___example_com_string_json,
-        })
+
+        try {
+          standaloneCode(ajv)
+        } catch (err) {
+          if (err instanceof Error) {
+            const isMappingErr =
+              `CodeGen: invalid export name: ${numSchema.$id}, use explicit $id name mapping` ===
+                err.message ||
+              `CodeGen: invalid export name: ${strSchema.$id}, use explicit $id name mapping` ===
+                err.message
+            assert.strictEqual(isMappingErr, true)
+          } else {
+            throw err
+          }
+        }
       })
     })
 
@@ -295,7 +302,7 @@ describe("standalone code generation", () => {
   })
 
   it("should generate module code with a single export - ESM", () => {
-    const ajv = new _Ajv({code: {source: true, exportEsm: true}})
+    const ajv = new _Ajv({code: {source: true, esm: true}})
     const v = ajv.compile({
       type: "number",
       minimum: 0,