chore(node): drop node v4 and v5 (#917) (#157)

This drops support for node v4 and v5. Neither is currently supported by
the Node.js team, nor by the `npm` CLI team, so it's hard to justify we
continue to support it.

The new minimum supported version is v6.

This also fixes a bug in the check-node-support script.

Issue shelljs/shelljs#873

.travis.yml

@@ -1,8 +1,6 @@
 language: node_js
 sudo: false
 node_js:
-  - 4
-  - 5
   - 6
   - 7
   - 8

README.md

@@ -10,7 +10,7 @@
 commands, providing an easy solution for simple Unix-like, cross-platform
 commands in npm package scripts.
 
-`shx` is proudly tested on every node release since <!-- start minVersion -->`v4`<!-- stop minVersion -->!
+`shx` is proudly tested on every node release since <!-- start minVersion -->`v6`<!-- stop minVersion -->!
 
 ## Difference Between ShellJS and shx
 

appveyor.yml

@@ -5,8 +5,6 @@ environment:
     - nodejs_version: '8'
     - nodejs_version: '7'
     - nodejs_version: '6'
-    - nodejs_version: '5'
-    - nodejs_version: '4'
 
 version: '{build}'
 

package.json

@@ -75,6 +75,6 @@
     "shelljs": "^0.8.1"
   },
   "engines": {
-    "node": ">=4"
+    "node": ">=6"
   }
 }

scripts/check-node-support.js

@@ -8,7 +8,7 @@ var yaml = require('js-yaml');
 var shell = require('shelljs');
 
 // This is the authoritative list of supported node versions.
-var MIN_NODE_VERSION = 4;
+var MIN_NODE_VERSION = 6;
 var MAX_NODE_VERSION = 10;
 
 function checkReadme(minNodeVersion) {
@@ -19,7 +19,7 @@ function checkReadme(minNodeVersion) {
       start + '\\s*' + formattedMinVersion + '\\s*' + stop, '');
   var readme = path.join(__dirname, '..', 'README.md');
   var match = shell.grep(expectedReadmeRegex, readme);
-  if (!match.toString()) {
+  if (!match.toString().trim()) {
     var msg = 'Update README to specify the min supported version. Look for "'
         + start + '"';
     throw new Error(msg);