fix for node 6

package.json

@@ -70,15 +70,15 @@
     "istanbul": "^0.4.0",
     "mocha": "^6.2.2",
     "ntypescript": "^1.201507091536.1",
-    "pify": "^5.0.0",
     "proxyquire": "^2.0.0",
     "react": "^16.0.0",
     "rimraf": "^3.0.0",
     "semver": "^7.1.3",
     "tslint": "^6.1.0",
     "tslint-config-standard": "^9.0.0",
     "typescript": "^3.7.2",
-    "typescript-json-schema": "^0.42.0"
+    "typescript-json-schema": "^0.42.0",
+    "util.promisify": "^1.0.1"
   },
   "peerDependencies": {
     "typescript": ">=2.7"

src/externs.d.ts

@@ -1,4 +1,4 @@
-declare module 'pify' {
+declare module 'util.promisify' {
   const _export: typeof import('util').promisify
   export = _export
 }

src/index.spec.ts

@@ -5,8 +5,8 @@ import semver = require('semver')
 import ts = require('typescript')
 import proxyquire = require('proxyquire')
 import { register, create, VERSION } from './index'
-import { mkdtempSync, readdirSync, copyFileSync, rmdirSync, unlinkSync, existsSync } from 'fs'
-import * as promisify from 'pify'
+import { mkdtempSync, readdirSync, copyFileSync, rmdirSync, unlinkSync, existsSync, readFileSync, writeFileSync } from 'fs'
+import * as promisify from 'util.promisify'
 
 const execP = promisify(exec)
 
@@ -25,7 +25,7 @@ before(async function () {
   const tempDir = mkdtempSync(join(TEST_DIR, 'tmp'))
   await execP(`npm pack --ignore-scripts "${ROOT_DIR}"`, { cwd: tempDir })
   const tarballPath = join(tempDir, readdirSync(tempDir)[0])
-  copyFileSync(tarballPath, TARBALL_PATH)
+  writeFileSync(TARBALL_PATH, readFileSync(tarballPath))
   unlinkSync(tarballPath)
   rmdirSync(tempDir)
   await execP(`npm install`, { cwd: TEST_DIR })