index.test.ts

import { transformSync } from '@swc/core'
import path from 'path'

import { AliasPathResolver } from './index'

test('named `src` imports', () => {
  // create resolved path.
  const out = transformSync(
    `
    import { woof } from 'src/lib/dog.ts'
    `,
    {
      plugin: (m) =>
        new AliasPathResolver({
          aliasPath: __dirname,
          // let's pretend file is in `src/services/dogService/dogService.ts`
          sourcePath: path.join(__dirname, 'services/dogServices/index.ts'),
        }).visitProgram(m),
    }
  )
  expect(out.code).toMatchInlineSnapshot(`
    "import { woof } from '../../lib/dog.ts';
    "
  `)
})

test('default `src` imports', () => {
  // create resolved path.
  const out = transformSync(
    `
    import X from 'src/lib/dog.ts'
    `,
    {
      plugin: (m) =>
        new AliasPathResolver({
          aliasPath: __dirname,
          // let's pretend file is in `src/services/dogService/dogService.ts`
          sourcePath: path.join(__dirname, 'services/dogServices/index.ts'),
        }).visitProgram(m),
    }
  )
  expect(out.code).toMatchInlineSnapshot(`
    "import X from '../../lib/dog.ts';
    "
  `)
})

test('named `src` exports', () => {
  // create resolved path.
  const out = transformSync(
    `
    export { woof } from 'src/lib/dog.ts'
    `,
    {
      plugin: (m) =>
        new AliasPathResolver({
          aliasPath: __dirname,
          // let's pretend file is in `src/services/dogService/dogService.ts`
          sourcePath: path.join(__dirname, 'services/dogServices/index.ts'),
        }).visitProgram(m),
    }
  )
  expect(out.code).toMatchInlineSnapshot(`
    "export { woof } from '../../lib/dog.ts';
    "
  `)
})

test('default `src` exports', () => {
  // create resolved path.
  const out = transformSync(
    `
    export * as Dog from 'src/lib/dog.ts'
    `,
    {
      plugin: (m) =>
        new AliasPathResolver({
          aliasPath: __dirname,
          // let's pretend file is in `src/services/dogService/dogService.ts`
          sourcePath: path.join(__dirname, 'services/dogServices/index.ts'),
        }).visitProgram(m),
    }
  )
  expect(out.code).toMatchInlineSnapshot(`
    "import * as _Dog from '../../lib/dog.ts';
    export { _Dog as Dog };
    "
  `)
})

swc-src-alias.ts

import {
  ExportNamedDeclaration,
  ImportDeclaration,
  ModuleDeclaration,
} from '@swc/core'
import Visitor from '@swc/core/Visitor'
import path from 'path'

interface AliasPathOptions {
  /** the absolute path to your `src` directory */
  aliasPath: string
  /** the path to the source file */
  sourcePath: string
}

export class AliasPathResolver extends Visitor {
  options: AliasPathOptions

  constructor(options: AliasPathOptions) {
    super()
    this.options = options
  }

  replaceImportPath = (value: string) => {
    const absAliasPath = path.join(this.options.aliasPath, value.substring(4))

    let newImportPath = path.relative(
      path.dirname(this.options.sourcePath),
      absAliasPath
    )
    if (newImportPath.indexOf('.') !== 0) {
      newImportPath = './' + newImportPath
    }
    return newImportPath
  }

  visitImportDeclaration(n: ImportDeclaration): ImportDeclaration {
    if (n.source.value.startsWith('src/')) {
      n.source.value = this.replaceImportPath(n.source.value)
    }
    return n
  }

  visitExportNamedDeclaration(n: ExportNamedDeclaration): ModuleDeclaration {
    if (n?.source?.value.startsWith('src/')) {
      n.source.value = this.replaceImportPath(n.source.value)
    }
    return n
  }
}