feat: Support NO_COLOR standard

stevenmhunt · medikoo · commit 8f2a4eb92341 · 2019-10-09T16:20:27.000+02:00
https://no-color.org/ BREAKING CHANGE: ANSI color codes won't be generated for output, when NO_COLOR env var is set
diff --git a/bare.js b/bare.js
@@ -15,6 +15,7 @@ var d              = require("d")
   , max            = Math.max
   , min            = Math.min
   , variantModes   = primitiveSet("_fg", "_bg")
+  , supportsColor  = require("./lib/supports-color")
   , xtermMatch
   , getFn;
 
@@ -85,6 +86,9 @@ getFn = function () {
 				null,
 				true
 			);
+			if (!supportsColor.isColorSupported()) {
+				return msg;
+			}
 			return start + msg + end;
 		},
 		proto
diff --git a/lib/supports-color.js b/lib/supports-color.js
@@ -0,0 +1,25 @@
+"use strict";
+
+// store whether supports-color mode is enabled or not.
+var state = null;
+
+// force supports-color mode
+var enableColor = function () { state = true; };
+
+// disable supports-color mode
+var disableColor = function () { state = false; };
+
+// use the NO_COLOR environment variable (default)
+var autoDetectSupport = function () { state = null; };
+
+// determine whether supports-color mode is enabled.
+var isColorSupported = function () {
+	if (state === null) {
+		return !process.env.NO_COLOR;
+	}
+	return state;
+};
+
+module.exports = {
+	enableColor: enableColor, disableColor: disableColor, autoDetectSupport: autoDetectSupport, isColorSupported: isColorSupported
+};
diff --git a/test/_lib/supports-color-wrapper.js b/test/_lib/supports-color-wrapper.js
@@ -0,0 +1,15 @@
+"use strict";
+var supportsColor = require("../../lib/supports-color");
+
+// a wrapper function which automatically forces color mode to enabled during the tests.
+module.exports = function (fn) {
+    return function (t, a) {
+        supportsColor.enableColor();
+        try {
+            return fn(t, a);
+        }
+        finally {
+            supportsColor.autoDetectSupport();
+        }
+    };
+};
diff --git a/test/art.js b/test/art.js
@@ -1,8 +1,9 @@
 "use strict";
 
 var clc = require("../");
+var wrapper = require("./_lib/supports-color-wrapper");
 
-module.exports = function (t, a) {
+module.exports = wrapper(function (t, a) {
 	a(
 		t("ooo", { o: clc.yellow("x") }), "\x1b[33mx\x1b[39m\x1b[33mx\x1b[39m\x1b[33mx\x1b[39m",
 		"Basic art"
@@ -19,4 +20,4 @@ module.exports = function (t, a) {
 	a(t("o\no", { o: clc.yellow("x") }), "\x1b[33mx\x1b[39m\n\x1b[33mx\x1b[39m", "Multiline art");
 
 	a(t("ooo", {}), "ooo", "Only text art");
-};
+});
diff --git a/test/bare.js b/test/bare.js
@@ -1,6 +1,8 @@
 "use strict";
+var supportsColor = require("../lib/supports-color");
+var wrapper = require("./_lib/supports-color-wrapper");
 
-module.exports = function (t, a) {
+module.exports = wrapper(function (t, a) {
 	var x, y;
 
 	a(t("test"), "test", "Plain");
@@ -397,4 +399,9 @@ module.exports = function (t, a) {
 			"Xterm"
 		);
 	}
-};
+
+	supportsColor.disableColor();
+	a(t.red("foo"), "foo", "Foreground with NO_COLOR");
+	a(t.bgRed("foo", "bar"), "foo bar", "Background with NO_COLOR");
+	a(t.blue.bgYellow("foo", "bar"), "foo bar", "Foreground & Background with NO_COLOR");
+});
diff --git a/test/lib/supports-color.js b/test/lib/supports-color.js
@@ -0,0 +1,11 @@
+"use strict";
+var wrapper = require("../_lib/supports-color-wrapper");
+
+module.exports = wrapper(function (t, a) {
+	t.enableColor();
+	a(t.isColorSupported(), true, "Enable color support NO_COLOR");
+	t.disableColor();
+	a(t.isColorSupported(), false, "Disable color support NO_COLOR");
+	t.autoDetectSupport();
+	a(t.isColorSupported(), !process.env.NO_COLOR, "use NO_COLOR env variable");
+});
diff --git a/test/throbber.js b/test/throbber.js
@@ -26,14 +26,19 @@ module.exports = {
 		t.stderr.on("data", function (data) { err += data; });
 		t.on("exit", function () {
 			a.ok(out.length > 4, "Interval");
-			a(
-				startsWith.call(
-					out.join(""),
-					"START\x1b[31m-\x1b[39m\x1b[31m\b\\\x1b" +
-						"[39m\x1b[31m\b|\x1b[39m\x1b[31m\b/\x1b[39m\x1b[31m\b-\x1b[39m"
-				),
-				true, "Output"
-			);
+			var isNoColor = Boolean(process.env.NO_COLOR);
+			if (isNoColor) {
+				a(startsWith.call(out.join(""), "START"), true, "Output");
+			} else {
+				a(
+					startsWith.call(
+						out.join(""),
+						"START\x1b[31m-\x1b[39m\x1b[31m\b\\\x1b" +
+							"[39m\x1b[31m\b|\x1b[39m\x1b[31m\b/\x1b[39m\x1b[31m\b-\x1b[39m"
+					),
+					true, "Output"
+				);
+			}
 			a(err, "", "No stderr output");
 			d();
 		});
