build: make Travis CI version compare readable

.travis.yml

@@ -21,33 +21,39 @@ cache:
   directories:
     - node_modules
 before_install:
+  - |
+    function v () {
+      tr '.' '\n' <<< "${1}" \
+        | awk '{ printf "%03d", $0 }' \
+        | sed 's/^0*//'
+    }
   # Configure npm
   - |
     # Skip updating shrinkwrap / lock
     npm config set shrinkwrap false
   # Setup Node.js version-specific dependencies
   - |
     # mocha for testing
-    # - use 1.x for Node.js < 0.8
-    # - use 2.x for Node.js < 0.10
-    # - use 3.x for Node.js < 6
-    if [[ "$(cut -d. -f1 <<< "$TRAVIS_NODE_VERSION")" -eq 0 && "$(cut -d. -f2 <<< "$TRAVIS_NODE_VERSION")" -lt 8 ]]; then
+    if [[ "$(v "$TRAVIS_NODE_VERSION")" -lt "$(v '0.8')" ]]; then
+      # - use 1.x for Node.js < 0.8
       npm install --save-dev mocha@1.21.5
-    elif [[ "$(cut -d. -f1 <<< "$TRAVIS_NODE_VERSION")" -eq 0 && "$(cut -d. -f2 <<< "$TRAVIS_NODE_VERSION")" -lt 10 ]]; then
+    elif [[ "$(v "$TRAVIS_NODE_VERSION")" -lt "$(v '0.10')" ]]; then
+      # - use 2.x for Node.js < 0.10
       npm install --save-dev mocha@2.5.3
-    elif [[ "$(cut -d. -f1 <<< "$TRAVIS_NODE_VERSION")" -lt 6 ]]; then
+    elif [[ "$(v "$TRAVIS_NODE_VERSION")" -lt "$(v '6.0')" ]]; then
+      # - use 3.x for Node.js < 6
       npm install --save-dev mocha@3.5.3
     fi
   - |
     # nyc for coverage
-    # - remove on Node.js < 6
-    if [[ "$(cut -d. -f1 <<< "$TRAVIS_NODE_VERSION")" -lt 6 ]]; then
+    if [[ "$(v "$TRAVIS_NODE_VERSION")" -lt "$(v '6.0')" ]]; then
+      # - remove on Node.js < 6
       npm rm --save-dev nyc
     fi
   - |
     # eslint for linting
-    # - remove on Node.js < 6
-    if [[ "$(cut -d. -f1 <<< "$TRAVIS_NODE_VERSION")" -lt 6 ]]; then
+    if [[ "$(v "$TRAVIS_NODE_VERSION")" -lt "$(v '6.0')" ]]; then
+      # - remove on Node.js < 6
       node -pe 'Object.keys(require("./package").devDependencies).join("\n")' | \
         grep -E '^eslint(-|$)' | \
         xargs npm rm --save-dev