chore: Add API doc

README.md

@@ -87,4 +87,7 @@ module.exports = {
 }
 ```
 
+## [API](https://github.com/JuniorTour/vue-template-babel-compiler/blob/main/doc/API.md)
+
+
 ### Welcome for Issues && PR.

doc/API.md

@@ -0,0 +1,109 @@
+# API of vue-template-babel-compiler
+
+## transpile(renderSourceCode: String, options: Object): String
+- Desc:
+
+Transpile es2015+ render function into standard es2015.
+
+Same as [vue-template-es2015-compiler](https://github.com/vuejs/vue-template-es2015-compiler).
+
+But use [Babel](https://babeljs.io/) to transpile.
+
+- Params:
+  - `renderSourceCode: String`: Source code of render function in string type.
+  - `options: Object`: Available options for transpile and Babel.
+    - (Work in progress, Welcome for contribution)
+- Return Value:
+  - String value, the `renderSourceCode: String` after transpile into standard es2015.
+
+- Usage Demo:
+```js
+const transpile = require('./lib')
+
+const renderFunctionBody = `
+var __render__ = function () {
+  with (this) {
+    return _c(
+      'div', {attrs: {"id": "app"}},
+      [
+        _c('h1', [_v("Hello vue-template-babel-compiler")]),
+        _v(" "),
+        (optional?.chaining)
+          ? _c('h2', [_v("\\n      Optional Chaining enabled: " + _s(optional?.chaining) + "\\n    ")])
+          : _e()
+      ]
+    )
+  }
+}
+`
+
+const afterTranspile = transpile(renderFunctionBody, {transforms: {stripWithFunctional: false}})
+
+// afterTranspile ===
+var __render__ = function () {
+  var _vm$optional, _vm$optional2;
+
+  var _vm=this;
+  var _h=_vm.$createElement;
+  var _c=_vm._self._c||_h;
+
+  return _c('div', {
+    attrs: {
+      "id": "app"
+    }
+  }, [
+    _c('h1', [_vm._v("Hello vue-template-babel-compiler")]),
+    _vm._v(" "),
+    (_vm$optional = _vm.optional) !== null && _vm$optional !== void 0 && _vm$optional.chaining
+      ? _c('h2', [
+        _vm._v("\n      Optional Chaining enabled: " + _vm._s((_vm$optional2 = _vm.optional) === null || _vm$optional2 === void 0
+          ? void 0
+          : _vm$optional2.chaining) + "\n    ")])
+      : _vm._e()
+    ]
+  );
+}
+
+// More: /test/compileRender.spec.js
+```
+
+## transpile.compile(templateSourceCode: String, options: Object): Object
+- Desc:
+
+Compile `<template>` of [Vue.js SFC](https://vuejs.org/v2/guide/single-file-components.html) into renders in standard es2015.
+
+Same as [vue-template-compiler](https://github.com/vuejs/vue/tree/dev/packages/vue-template-compiler).
+
+But use [Babel](https://babeljs.io/) to transpile.
+
+- Params:
+  - `templateSourceCode: String`: Source code of render function in string type.
+  - `options: Object`: Available options for compile `<template>` and Babel.
+    - (Work in progress, Welcome for contribution)
+- Return Value: Object
+```ts
+{
+  ast: ?ASTElement, // parsed template elements to AST
+  render: string,   // main render function code
+  staticRenderFns: Array<string>, // render code for static sub trees, if any
+  errors: Array<string> // template syntax errors, if any
+}
+```
+
+- Usage Demo:
+```js
+const Compiler = require('./lib')
+
+const {ast, render, staticRenderFns, tips, errors} = Compiler.compile(`<div>Hello vue-template-babel-compiler</div>`)
+
+// render ===
+var _vm=this;
+var _h=_vm.$createElement;
+var _c=_vm._self._c||_h;
+
+return _c('div', [_vm._v("Hello vue-template-babel-compiler")]);
+
+// More: /test/compileTemplate.spec.js
+```
+
+## More...