Drop old node.js support without Buffer.from (#702)

Author: blakeembrey

package-lock.json

@@ -49,7 +49,6 @@
   "homepage": "https://github.com/TypeStrong/ts-node",
   "devDependencies": {
     "@types/arrify": "^1.0.1",
-    "@types/buffer-from": "^1.1.0",
     "@types/chai": "^4.0.4",
     "@types/diff": "^3.2.1",
     "@types/minimist": "^1.2.0",
@@ -77,7 +76,6 @@
   },
   "dependencies": {
     "arrify": "^1.0.0",
-    "buffer-from": "^1.1.0",
     "diff": "^3.1.0",
     "make-error": "^1.1.1",
     "minimist": "^1.2.0",

package.json

@@ -6,7 +6,6 @@ import mkdirp = require('mkdirp')
 import crypto = require('crypto')
 import yn = require('yn')
 import arrify = require('arrify')
-import bufferFrom = require('buffer-from')
 import { BaseError } from 'make-error'
 import * as util from 'util'
 import * as ts from 'typescript'
@@ -487,7 +486,7 @@ type SourceOutput = [string, string]
  * Update the output remapping the source map.
  */
 function updateOutput (outputText: string, fileName: string, sourceMap: string, getExtension: (fileName: string) => string) {
-  const base64Map = bufferFrom(updateSourceMap(sourceMap, fileName), 'utf8').toString('base64')
+  const base64Map = Buffer.from(updateSourceMap(sourceMap, fileName), 'utf8').toString('base64')
   const sourceMapContent = `data:application/json;charset=utf-8;base64,${base64Map}`
   const sourceMapLength = `${basename(fileName)}.map`.length + (getExtension(fileName).length - extname(fileName).length)