ast-grep replace import to export.md

Rewrite "import then re-export" to a direct "re-export" approach via ast-grep.

Rule file see in file-import-to-export.yml

Preview Effect

- import Form, {
+ export {
+   default as Form,
    type FormLayout,
    FormNode as Node,
  } from 'src/components/Form';
- export {
-   Form,
-   FormLayout,
-   Node,
- }

- import Tooltip from 'src/components/Button';
+ export { default as Tooltip } from 'src/components/Button';
- export { Tooltip }

- import { Button, type ButtonOption } from 'src/components/Button';
+ export { Button, type ButtonOption } from 'src/components/Button';
- export { Button, type ButtonOption }
  
- import type { CascaderOptionType } from 'src/components/Cascader';
+ export type { CascaderOptionType } from 'src/components/Cascader';
- export { CascaderOptionType }

Assumptions

• All import are ONLY used to re-export
  • implies that all identifier in import statements are NOT used in the code, except for in re-export
• NO renaming in re-export, ONLY have renaming in import statements
  • due to the ast-grep cannot calculate renaming back in import
• NO export default statement

References

• ast-grep Playground

• https://ast-grep.github.io

import-to-export.yml

# [Rule File](https://ast-grep.github.io/guide/rule-config.html#rule-file)

id: import-to-export
message: rewrite import and re-export to pure re-export
severity: info # error, warning, info, hint
language: TypeScript

# use:
#   ast-grep scan --color=always --update-all --filter=import-to-export
#   git diff

note: |
  1. remore all `export {}`
  2. replace `import {}` to `export {}`,  `import * as XXX` to `export * as XXX`
  3. replace `import Default` to `export { default as Default }`
  4. replace `import Default, { ... }` to `export { default as Default, ... }`
  
# step.1, remore all `export {}`
rule:
  kind: export_statement
  has:
    kind: export_clause
  not:
    has:
      kind: string

fix: ''

---

# step.2, replace `import {}` to `export {}`,  `import * as XXX` to `export * as XXX`
rule:
  pattern: import
  precedes:
    kind: import_clause
    has:
      any:
        - kind: named_imports
        - kind: namespace_import
    not:
      has:
        # default import
        kind: identifier
    stopBy: end

fix: export

---

# step.3, replace `import Default` to `export { default as Default }`

utils:
  IMPORT_STATEMENT:
    kind: import_statement
    any:
      - pattern: import $$$IMPORT_TYPE $IMPORT_DEFAULT from '$$$'
      - pattern: import $$$IMPORT_TYPE $IMPORT_DEFAULT from "$$$"
    has:
      matches: FROM_FRAGMENT
      stopBy: end

  FROM_FRAGMENT:
    kind: string_fragment
    pattern: $FROM_FRAGMENT
    inside:
      kind: import_statement
      stopBy: end

rule:
  matches: IMPORT_STATEMENT
  has:
    kind: import_clause
    pattern: $IMPORT_DEFAULT
    not:
      has:
        any:
          - kind: named_imports
          - kind: namespace_import

transform:
  TYPED:
    replace:
      source: $$$IMPORT_TYPE
      replace: '^.+$'
      by: ' type'

fix: export {$TYPED default as $IMPORT_DEFAULT } from '$FROM_FRAGMENT';


---

# step.4, replace `import Default, { ... }` to `export { default as Default, ... }`

utils:
  IMPORT_STATEMENT:
    kind: import_statement
    any:
      - pattern: import $$$IMPORT_TYPE $IMPORT_CLAUSS from '$$$'
      - pattern: import $$$IMPORT_TYPE $IMPORT_CLAUSS from "$$$"
    has:
      matches: FROM_FRAGMENT
      stopBy: end

  FROM_FRAGMENT:
    kind: string_fragment
    pattern: $FROM_FRAGMENT
    inside:
      kind: import_statement
      stopBy: end

  IMPORT_DEFAULT:
    kind: identifier
    pattern: $IMPORT_DEFAULT
    inside:
      kind: import_clause
  
  NAMED_IMPORTS:
    kind: named_imports
    pattern: $NAMED_IMPORTS
    inside:
      kind: import_clause

rule:
  matches: IMPORT_STATEMENT
  has:
    kind: import_clause
    has:
      matches: IMPORT_DEFAULT
      precedes:
        matches: NAMED_IMPORTS
        stopBy: end

transform:
  TYPED:
    replace:
      source: $$$IMPORT_TYPE
      replace: '^.+$'
      by: 'type '
  NAMED_EXPORT:
    # '{ xxx, xxx }' => ' xxx, xxx '
    # '{\n  xxx,\n  xxx,\n}' => '\n  xxx,\n  xxx,\n'
    substring:
      source: $NAMED_IMPORTS
      startChar: 1
      endChar: -1
  SPACING:
    # '{ xxx, xxx }' => ' '
    # '{\n  xxx,\n  xxx,\n}' => '\n  '
    replace:
      source: $NAMED_IMPORTS
      replace: ^\{(?P<spacing>\s+)\w(.|\n)*$
      by: '$spacing'

fix: export {$SPACING$TYPEDdefault as $IMPORT_DEFAULT,$NAMED_EXPORT} from '$FROM_FRAGMENT';

unit-test-cases.ts

// ------------- Bare import, Do nothing -------------
import './index.less'


// ------------- import and re-export, replace import as the follow export -------------

import Form from 'src/components/Form';
export { default as Form } from 'src/components/Form';

import type Form from 'src/components/Form';
export { type default as Form } from 'src/components/Form';


import Form from "src/components/Form";
export { default as Form } from 'src/components/Form';

import type Form from "src/components/Form";
export { type default as Form } from 'src/components/Form';

import Form, { FormLayout, FormNode as Node } from 'src/components/Form';
export { default as Form, FormLayout, FormNode as Node } from 'src/components/Form';

import Form, { type FormLayout, FormNode as Node } from 'src/components/Form';
export { default as Form, type FormLayout, FormNode as Node } from 'src/components/Form';

import { Form, FormLayout, FormNode as Node } from 'src/components/Form';
export { Form, FormLayout, FormNode as Node } from 'src/components/Form';

import { Form, type FormLayout, type FormNode as Node } from 'src/components/Form';
export { Form, type FormLayout, type FormNode as Node } from 'src/components/Form';

import type { Form, FormLayout, FormNode as Node } from 'src/components/Form';
export type { Form, FormLayout, FormNode as Node } from 'src/components/Form';

import * as Form from 'src/components/RendererEditor/globalEditors';
export * as Form from 'src/components/RendererEditor/globalEditors';


import type * as Form from 'src/components/RendererEditor/globalEditors';
export type * as Form from 'src/components/RendererEditor/globalEditors';

import Form, {
  type FormLayout,
  FormNode as Node,
} from 'src/components/Form';
export {
  default as Form,
  type FormLayout,
  FormNode as Node,
} from 'src/components/Form';


import type Form, {
  type FormLayout,
  FormNode as Node,
} from 'src/components/Form';
export {
  type default as Form,
  type FormLayout,
  FormNode as Node,
} from 'src/components/Form';


import {
  Form,
  type FormLayout,
  FormNode as Node,
} from 'src/components/Form';
export {
  Form,
  type FormLayout,
  FormNode as Node,
} from 'src/components/Form';


import type {
  Form,
  FormLayout,
  FormNode as Node,
} from 'src/components/Form';
export {
  Form,
  FormLayout,
  FormNode as Node,
} from 'src/components/Form';


// ------------- Bare re-export, Remove -------------
//   `export as RENAMED` is rename while export, but not rename in import, 
//   just remove it will cause issue

export { Form, FormLayout, FormNode as Node }

export { type Form, FormLayout, type FormNode as Node }

export type { Form, FormLayout, FormNode as Node }


// -------------  Do nothing -------------
export const cs = 'adg'

export const cs = {}

export function ast() {}

export class Ast {
  cs = ''
}

export type asg = string

export default cs