Better test

.babelrc

@@ -1,4 +1,12 @@
 {
-  "plugins": ["@babel/plugin-proposal-function-bind"],
-  "presets": ["@babel/preset-env"]
+  "presets": [
+    [
+      "@babel/preset-env",
+      {
+        "targets": {
+          "node": "10"
+        }
+      }
+    ]
+  ]
 }

.travis.yml

@@ -1,6 +1,4 @@
 language: node_js
 node_js:
-- node   # Current stable, i.e. 13 in October, 2019
-- lts/*  # Most recent LTS version, i.e. 12 in October, 2019
-- 10     # Explicitly include an active LTS version
-- 8      # Explicitly include the maintenance LTS version
+  - 14
+  - 12

Makefile

@@ -4,4 +4,4 @@ LIB = $(SRC:src/%.js=lib/%.js)
 lib: $(LIB)
 lib/%.js: src/%.js
 	mkdir -p $(@D)
-	babel $< -o $@
+	./node_modules/.bin/babel $< -o $@