feat(config): exposes custom transformers to config for presets

src/__helpers__/fakers.ts

@@ -57,6 +57,7 @@ export function tsJestConfig(options?: Partial<TsJestConfig>): TsJestConfig {
   return {
     isolatedModules: false,
     compiler: 'typescript',
+    transformers: [],
     babelConfig: undefined,
     tsConfig: undefined,
     stringifyContentPathRegex: undefined,

src/compiler.ts

@@ -35,10 +35,8 @@ import stableStringify = require('fast-json-stable-stringify')
 import { readFileSync, writeFileSync } from 'fs'
 import mkdirp = require('mkdirp')
 import { basename, extname, join, relative } from 'path'
-import { CustomTransformers } from 'typescript'
 
 import { ConfigSet } from './config/config-set'
-import { factory as customTransformersFactory } from './transformers'
 import { MemoryCache, TsCompiler, TypeInfo } from './types'
 import { Errors, interpolate } from './util/messages'
 import { sha1 } from './util/sha1'
@@ -88,8 +86,7 @@ export function createCompiler(configs: ConfigSet): TsCompiler {
       ? (path: string) => (/\.[tj]sx$/.test(path) ? '.jsx' : '.js')
       : (_: string) => '.js'
 
-  // TODO: grab internal transformers
-  const transformers: CustomTransformers = customTransformersFactory(configs)
+  const transformers = configs.tsCustomTransformers
 
   /**
    * Create the basic required function using transpile mode.

src/config/__snapshots__/config-set.spec.ts.snap

@@ -32,6 +32,7 @@ Object {
   },
   "isolatedModules": false,
   "stringifyContentPathRegex": undefined,
+  "transformers": Array [],
   "tsConfig": Object {
     "kind": "file",
     "value": undefined,

src/config/config-set.ts

@@ -13,11 +13,13 @@ import { existsSync, readFileSync } from 'fs'
 import json5 from 'json5'
 import { dirname, isAbsolute, join, resolve } from 'path'
 import semver from 'semver'
-import { Diagnostic, FormatDiagnosticsHost, ParsedCommandLine } from 'typescript'
+import { CustomTransformers, Diagnostic, FormatDiagnosticsHost, ParsedCommandLine } from 'typescript'
 
 import { version as myVersion } from '..'
 import { createCompiler } from '../compiler'
+import { internals as internalAstTransformers } from '../transformers'
 import {
+  AstTransformerDesc,
   BabelConfig,
   BabelJestTransformer,
   TTypeScript,
@@ -160,6 +162,9 @@ export class ConfigSet {
       }
     }
 
+    // transformers
+    const transformers = (options.astTransformers || []).map(mod => this.resolvePath(mod, { nodeResolve: true }))
+
     // babel jest
     const { babelConfig: babelConfigOpt } = options
     let babelConfig: TsJestConfig['babelConfig']
@@ -210,6 +215,7 @@ export class ConfigSet {
       diagnostics,
       isolatedModules: !!options.isolatedModules,
       compiler: options.compiler || 'typescript',
+      transformers,
       stringifyContentPathRegex,
     }
     this.logger.debug({ tsJestConfig: res }, 'normalized ts-jest config')
@@ -316,6 +322,18 @@ export class ConfigSet {
     return createCompiler(this)
   }
 
+  @Memoize()
+  get astTransformers(): AstTransformerDesc[] {
+    return [...internalAstTransformers, ...this.tsJest.transformers.map(m => require(m))]
+  }
+
+  @Memoize()
+  get tsCustomTransformers(): CustomTransformers {
+    return {
+      before: this.astTransformers.map(t => t.factory(this)),
+    }
+  }
+
   @Memoize()
   get hooks(): TsJestHooksMap {
     let hooksFile = process.env.TS_JEST_HOOKS
@@ -487,14 +505,32 @@ export class ConfigSet {
     return { input, resolved: result }
   }
 
-  resolvePath(inputPath: string, noFailIfMissing = false): string {
+  resolvePath(
+    inputPath: string,
+    { throwIfMissing = true, nodeResolve = false }: { throwIfMissing?: boolean; nodeResolve?: boolean } = {},
+  ): string {
     let path: string = inputPath
+    let nodeResolved = false
     if (path.startsWith('<rootDir>')) {
       path = resolve(this.rootDir, path.substr(9))
     } else if (!isAbsolute(path)) {
-      path = resolve(this.cwd, path)
+      if (!path.startsWith('.') && nodeResolve) {
+        try {
+          path = require.resolve(path)
+          nodeResolved = true
+        } catch (_) {}
+      }
+      if (!nodeResolved) {
+        path = resolve(this.cwd, path)
+      }
+    }
+    if (!nodeResolved && nodeResolve) {
+      try {
+        path = require.resolve(path)
+        nodeResolved = true
+      } catch (_) {}
     }
-    if (!noFailIfMissing && !existsSync(path)) {
+    if (throwIfMissing && !existsSync(path)) {
       throw new Error(interpolate(Errors.FileNotFound, { inputPath, resolvedPath: path }))
     }
     this.logger.debug({ fromPath: inputPath, toPath: path }, 'resolved path from', inputPath, 'to', path)
@@ -514,6 +550,7 @@ export class ConfigSet {
 
     return new JsonableValue({
       versions: this.versions,
+      transformers: this.astTransformers.map(t => `${t.name}@${t.version}`),
       jest,
       tsJest: this.tsJest,
       babel: this.babel,

src/transformers/README.md

@@ -13,6 +13,11 @@ import {
 } from 'typescript';
 import { ConfigSet } from '../config-set'
 
+// this is a unique identifier for your transformer
+export const name = 'my-transformer'
+// increment this each time you change the behavior of your transformer
+export const version = 1
+
 export function factory(cs: ConfigSet) {
   const ts = cs.compilerModule
   function createVisitor(ctx: TransformationContext, sf: SourceFile) {

src/transformers/hoisting.ts

@@ -19,6 +19,10 @@ import { ConfigSet } from '../config/config-set'
  */
 const HOIST_METHODS = ['mock', 'unmock']
 
+export const name = 'hoisting-jest-mock'
+// increment this each time the code is modified
+export const version = 1
+
 /**
  * The factory of hoisting transformer factory
  * @param cs Current jest configuration-set

src/transformers/index.ts

@@ -1,11 +1,5 @@
-import { CustomTransformers } from 'typescript'
+import { AstTransformerDesc } from '../types'
 
-import { ConfigSet } from '../config/config-set'
+import * as hoisting from './hoisting'
 
-import { factory as hoistingFactory } from './hoisting'
-
-export function factory(cs: ConfigSet): CustomTransformers {
-  return {
-    before: [hoistingFactory(cs)],
-  }
-}
+export const internals: AstTransformerDesc[] = [hoisting]

src/types.ts

@@ -1,5 +1,7 @@
 import * as _babel from 'babel__core'
-import _ts, { CompilerOptions } from 'typescript'
+import _ts, { CompilerOptions, SourceFile, TransformerFactory } from 'typescript'
+
+import { ConfigSet } from './config/config-set'
 
 export type TBabelCore = typeof _babel
 export type TTypeScript = typeof _ts
@@ -29,6 +31,11 @@ export interface TsJestGlobalOptions {
    */
   compiler?: string
 
+  /**
+   * Custom transformers (mostly used by jest presets)
+   */
+  astTransformers?: string[]
+
   /**
    * TS diagnostics - less to be reported if `isolatedModules` is `true`. It can be:
    *     - `true` (or `undefined`, it's the default): show all diagnostics
@@ -92,6 +99,7 @@ export interface TsJestConfig {
   compiler: string
   diagnostics: TsJestConfig$diagnostics
   babelConfig: TsJestConfig$babelConfig
+  transformers: string[]
 
   // to deprecate / deprecated === === ===
   stringifyContentPathRegex: TsJestConfig$stringifyContentPathRegex
@@ -158,3 +166,9 @@ export interface TsCompiler {
   compile(code: string, fileName: string, lineOffset?: number): string
   getTypeInfo(code: string, fileName: string, position: number): TypeInfo
 }
+
+export interface AstTransformerDesc {
+  name: string
+  version: number
+  factory(cs: ConfigSet): TransformerFactory<SourceFile>
+}