no-duplicated-vue-import.ts

import { LogContexts, LogLevels } from 'bs-logger'
import type { ConfigSet } from 'ts-jest/dist/config/config-set';
import type * as _ts from 'typescript'

// this is a unique identifier for your transformer. `ts-jest` uses this for jest cache key
export const name = 'no-duplicated-vue-import'
// increment this each time you change the behavior of your transformer. `ts-jest` uses this for jest cache key
export const version = 1
const VUE_GLOBAL_NAME = 'vue'
const ROOT_LEVEL_AST = 1

/**
 * @usage In jest config, define as
 * // jest.config.js
 * module.exports = {
 *   // other configs
 *   globals: {
 *     'ts-jest': {
 *       astTransformers: {
 *         after: ['vue-ts-jest/dist/transformers/vue-no-duplicated-import']
 *       }
 *     }
 *   }
 * }
 */
export function factory(cs: ConfigSet): (ctx: _ts.TransformationContext) => _ts.Transformer<_ts.SourceFile> {
  const logger = cs.logger.child({ namespace: 'vue-no-duplicated-import' })
  const ts = cs.compilerModule
  const isRequire = (node: _ts.Node): node is _ts.CallExpression =>
    ts.isCallExpression(node) &&
    ts.isIdentifier(node.expression) &&
    node.expression.text === 'require' &&
    ts.isStringLiteral(node.arguments[0]) &&
    node.arguments.length === 1
  const isDuplicatedGlobalVueImport = (node: _ts.Node) => ts.isVariableStatement(node)
    && node.declarationList.declarations[0].initializer
    && isRequire(node.declarationList.declarations[0].initializer)
    && (node.declarationList.declarations[0].initializer.arguments[0] as _ts.StringLiteral).text === VUE_GLOBAL_NAME
    && ts.isIdentifier(node.declarationList.declarations[0].name)
    /**
     * Handle import declaration import { defineComponent, ref } from 'vue' which doesn't generate Identifier text when
     * this transformer is executed
     */
    && !node.declarationList.declarations[0].name.text

  const createVisitor = (ctx: _ts.TransformationContext, _sf: _ts.SourceFile) => {
    /**
     * Current block level
     */
    let level = 0
    /**
     * List of nodes which needs to be deleted, indexed by their owning level
     */
    const toBeDeletedNodes: _ts.Statement[][] = []
    /**
     * Called when we enter a block to increase the level
     */
    const enter = () => {
      level++
      // reuse arrays
      if (toBeDeletedNodes[level]) {
        toBeDeletedNodes[level].splice(0, toBeDeletedNodes[level].length)
      }
    }
    /**
     * Called when we leave a block to decrease the level
     */
    const exit = () => level--
    /**
     * Adds a node to the list of nodes to be deleted in the current level
     */
    const gatherDeleteNodes = (node: _ts.Statement) => {
      if (toBeDeletedNodes[level]) {
        toBeDeletedNodes[level].push(node)
      } else {
        toBeDeletedNodes[level] = [node]
      }
    }
    const visitor: _ts.Visitor = node => {
      // enter this level
      enter()

      // visit each child
      let resultNode = ts.visitEachChild(node, visitor, ctx)
      // check if we have something to delete in this level
      if (toBeDeletedNodes[level]?.length) {
        const newNode = ts.getMutableClone(resultNode) as _ts.Block
        const otherStmts = (resultNode as _ts.Block).statements.filter(
          (s) => !toBeDeletedNodes[level].includes(s) && !isDuplicatedGlobalVueImport(s),
        )
        resultNode = {
          ...newNode,
          statements: ts.createNodeArray([...otherStmts]),
        } as _ts.Statement
      }

      // exit the level
      exit()

      if (isDuplicatedGlobalVueImport(resultNode) && level === ROOT_LEVEL_AST) {
        gatherDeleteNodes(resultNode as _ts.Statement)
      }

      // finally returns the currently visited node
      return resultNode
    }

    return visitor
  }

  // returns the transformer factory
  return (ctx: _ts.TransformationContext): _ts.Transformer<_ts.SourceFile> =>
    logger.wrap(
      { [LogContexts.logLevel]: LogLevels.debug, call: null },
      'visitSourceFileNode(): vue no duplicated import',
      (sf: _ts.SourceFile) => ts.visitNode(sf, createVisitor(ctx, sf)),
    )
}