feat: Add out-of-the-tbox typescript support (#38)

* Add doc.

* Migrated typescript code from cypress
Move through2 to dependencies.
Fix

* Add typescript.

* Add e2e tests for typescript.

* Test .tsx file.

* Reason why simple_tsify is necessary.

* Test typescript options + remove babelify even if it's not the last item

* Test tsx file with enzyme.

* Fix test failure.

* remove enzyme

* use arrow function syntax

* move files into lib directory

* remove duplicate file

* remove need to extra test files

* update error message

* move e2e tests to unit tests

* properly nest e2e tests

* make it clear where error is coming from

Co-authored-by: Chris Breiding <chrisbreiding@gmail.com>

README.md

@@ -146,6 +146,16 @@ browserify({
 })
 ```
 
+### typescript
+
+When the path to the TypeScript package is given, Cypress will automatically transpile `.ts` spec, plugin, support files. Note that this **DOES NOT** check types.
+
+```javascript
+browserify({
+  typescript: require.resolve('typescript')
+})
+```
+
 **Default**: `undefined`
 
 ## Modifying default options

index.js

@@ -2,7 +2,7 @@
 
 const path = require('path')
 const Promise = require('bluebird')
-const fs = require('./fs')
+const fs = require('./lib/fs')
 
 const cloneDeep = require('lodash.clonedeep')
 const browserify = require('browserify')
@@ -60,7 +60,7 @@ const defaultOptions = {
   },
 }
 
-const getBrowserifyOptions = (entry, userBrowserifyOptions = {}) => {
+const getBrowserifyOptions = (entry, userBrowserifyOptions = {}, typescriptPath = null) => {
   let browserifyOptions = cloneDeep(defaultOptions.browserifyOptions)
 
   // allow user to override default options
@@ -81,6 +81,36 @@ const getBrowserifyOptions = (entry, userBrowserifyOptions = {}) => {
     entries: [entry],
   })
 
+  if (typescriptPath) {
+    const transform = browserifyOptions.transform
+    const hasTsifyTransform = transform.some(([name]) => name.includes('tsify'))
+    const hastsifyPlugin = browserifyOptions.plugin.includes('tsify')
+
+    if (hasTsifyTransform || hastsifyPlugin) {
+      const type = hasTsifyTransform ? 'transform' : 'plugin'
+
+      throw new Error(`Error running @cypress/browserify-preprocessor:
+
+It looks like you passed the 'typescript' option and also specified a browserify ${type} for TypeScript. This may cause conflicts.
+
+Please do one of the following:
+
+1) Pass in the 'typescript' option and omit the browserify ${type} (Recommmended)
+2) Omit the 'typescript' option and continue to use your own browserify ${type}
+`)
+    }
+
+    browserifyOptions.extensions.push('.ts', '.tsx')
+    // remove babelify setting
+    browserifyOptions.transform = transform.filter(([name]) => !name.includes('babelify'))
+    // add typescript compiler
+    browserifyOptions.transform.push([
+      path.join(__dirname, './lib/simple_tsify'), {
+        typescript: require(typescriptPath),
+      },
+    ])
+  }
+
   debug('browserifyOptions: %o', browserifyOptions)
 
   return browserifyOptions
@@ -127,7 +157,7 @@ const preprocessor = (options = {}) => {
     debug('input:', filePath)
     debug('output:', outputPath)
 
-    const browserifyOptions = getBrowserifyOptions(filePath, options.browserifyOptions)
+    const browserifyOptions = getBrowserifyOptions(filePath, options.browserifyOptions, options.typescript)
     const watchifyOptions = Object.assign({}, defaultOptions.watchifyOptions, options.watchifyOptions)
 
     const bundler = browserify(browserifyOptions)
@@ -222,4 +252,12 @@ const preprocessor = (options = {}) => {
 // provide a clone of the default options
 preprocessor.defaultOptions = JSON.parse(JSON.stringify(defaultOptions))
 
+if (process.env.__TESTING__) {
+  preprocessor.reset = () => {
+    for (let filePath in bundles) {
+      delete bundles[filePath]
+    }
+  }
+}
+
 module.exports = preprocessor

lib/simple_tsify.js

@@ -0,0 +1,43 @@
+let through = require('through2')
+
+const isJson = (code) => {
+  try {
+    JSON.parse(code)
+  } catch (e) {
+    return false
+  }
+
+  return true
+}
+
+// tsify doesn't have transpile-only option like ts-node or ts-loader.
+// It means it should check types whenever spec file is changed
+// and it slows down the test speed a lot.
+// We skip this slow type-checking process by using transpileModule() api.
+module.exports = function (b, opts) {
+  const chunks = []
+
+  return through(
+    (buf, enc, next) => {
+      chunks.push(buf.toString())
+      next()
+    },
+    function (next) {
+      const ts = opts.typescript
+      const text = chunks.join('')
+
+      if (isJson(text)) {
+        this.push(text)
+      } else {
+        this.push(ts.transpileModule(text, {
+          compilerOptions: {
+            esModuleInterop: true,
+            jsx: 'react',
+          },
+        }).outputText)
+      }
+
+      next()
+    },
+  )
+}

package.json

@@ -52,10 +52,13 @@
     "mocha": "5.2.0",
     "mockery": "2.1.0",
     "nsp": "3.2.1",
+    "react": "16.13.1",
+    "react-dom": "16.13.1",
     "semantic-release": "15.13.15",
     "sinon": "7.2.3",
     "sinon-chai": "3.3.0",
-    "snap-shot-it": "7.9.2"
+    "snap-shot-it": "7.9.2",
+    "typescript": "3.8.3"
   },
   "dependencies": {
     "@babel/core": "7.4.5",
@@ -74,7 +77,8 @@
     "debug": "4.1.1",
     "fs-extra": "7.0.1",
     "lodash.clonedeep": "4.5.0",
-    "watchify": "3.11.1"
+    "watchify": "3.11.1",
+    "through2": "^2.0.0"
   },
   "release": {
     "analyzeCommits": {

test/e2e/e2e_spec.js

@@ -2,14 +2,17 @@ const chai = require('chai')
 const path = require('path')
 const snapshot = require('snap-shot-it')
 
-const fs = require('../../fs')
+process.env.__TESTING__ = true
+
+const fs = require('../../lib/fs')
 const preprocessor = require('../../index')
 
 /* eslint-disable-next-line no-unused-vars */
 const expect = chai.expect
 
-beforeEach(function () {
+beforeEach(() => {
   fs.removeSync(path.join(__dirname, '_test-output'))
+  preprocessor.reset()
 })
 
 // do not generate source maps by default
@@ -25,60 +28,80 @@ const bundle = (fixtureName, options = DEFAULT_OPTIONS) => {
   })
 }
 
-describe('browserify preprocessor - e2e', function () {
-  it('correctly preprocesses the file', function () {
+describe('browserify preprocessor - e2e', () => {
+  it('correctly preprocesses the file', () => {
     return bundle('example_spec.js').then((output) => {
       snapshot(output)
     })
   })
-})
 
-describe('imports and exports', () => {
-  it('handles imports and exports', () => {
-    return bundle('math_spec.js').then((output) => {
-      // check that bundled tests work
-      eval(output)
+  describe('imports and exports', () => {
+    it('handles imports and exports', () => {
+      return bundle('math_spec.js').then((output) => {
+        // check that bundled tests work
+        eval(output)
+      })
     })
-  })
 
-  it('named ES6', () => {
-    return bundle('divide_spec.js').then((output) => {
-      // check that bundled tests work
-      eval(output)
+    it('named ES6', () => {
+      return bundle('divide_spec.js').then((output) => {
+        // check that bundled tests work
+        eval(output)
+      })
     })
-  })
 
 
-  it('handles module.exports and import', () => {
-    return bundle('sub_spec.js').then((output) => {
-      // check that bundled tests work
-      eval(output)
-      snapshot('sub import', output)
+    it('handles module.exports and import', () => {
+      return bundle('sub_spec.js').then((output) => {
+        // check that bundled tests work
+        eval(output)
+        snapshot('sub import', output)
+      })
     })
-  })
 
-  it('handles module.exports and default import', () => {
-    return bundle('mul_spec.js').then((output) => {
-      // check that bundled tests work
-      eval(output)
-      // for some reason, this bundle included full resolved path
-      // to interop require module
-      // which on CI generates different path.
-      // so as long as eval works, do not snapshot it
+    it('handles module.exports and default import', () => {
+      return bundle('mul_spec.js').then((output) => {
+        // check that bundled tests work
+        eval(output)
+        // for some reason, this bundle included full resolved path
+        // to interop require module
+        // which on CI generates different path.
+        // so as long as eval works, do not snapshot it
+      })
+    })
+
+    it('handles default string import', () => {
+      return bundle('dom_spec.js').then((output) => {
+        // check that bundled tests work
+        eval(output)
+      })
     })
-  })
 
-  it('handles default string import', () => {
-    return bundle('dom_spec.js').then((output) => {
-      // check that bundled tests work
-      eval(output)
+    it('handles non-top-level require', () => {
+      return bundle('require_spec.js').then((output) => {
+        // check that bundled tests work
+        eval(output)
+      })
     })
   })
 
-  it('handles non-top-level require', () => {
-    return bundle('require_spec.js').then((output) => {
-      // check that bundled tests work
-      eval(output)
+  describe('typescript', () => {
+    it('handles .ts file when the path is given', () => {
+      return bundle('typescript/math_spec.ts', {
+        typescript: require.resolve('typescript'),
+      }).then((output) => {
+        // check that bundled tests work
+        eval(output)
+      })
+    })
+
+    it('handles .tsx file when the path is given', () => {
+      return bundle('typescript/react_spec.tsx', {
+        typescript: require.resolve('typescript'),
+      }).then((output) => {
+        // check that bundled tests work
+        eval(output)
+      })
     })
   })
 })

test/fixtures/typescript/component.tsx

@@ -0,0 +1,7 @@
+import React from 'react'
+
+export default () => {
+  return (
+    <div className="icon-star">icon</div>
+  )
+}

test/fixtures/typescript/math.ts

@@ -0,0 +1,5 @@
+export default {
+  add: (a: number, b: number) => {
+    return a + b
+  },
+}