Fix old bundlers and improve browser use

Closes GH-24.

Author: wooorm

lib/color.browser.js

@@ -0,0 +1 @@
+export const color = false

lib/color.js

@@ -0,0 +1,7 @@
+import supportsColor from 'supports-color'
+
+/** @type {boolean} */
+// @ts-expect-error Types are incorrect.
+const color = supportsColor.stderr.hasBasic
+
+export {color}

lib/index.js

@@ -30,17 +30,14 @@
  * @property {Sizes} sizes
  */
 
-import supportsColor from 'supports-color'
 import width from 'string-width'
 import {stringifyPosition} from 'unist-util-stringify-position'
 import {statistics} from 'vfile-statistics'
 import {sort} from 'vfile-sort'
+import {color} from './color.js'
 
 const own = {}.hasOwnProperty
 
-// @ts-expect-error Types are incorrect.
-const supported = supportsColor.stderr.hasBasic
-
 // `log-symbols` without chalk, ignored for Windows:
 /* c8 ignore next 4 */
 const chars =
@@ -162,7 +159,7 @@ function format(map, one, options) {
   /** @type {boolean} */
   const enabled =
     options.color === undefined || options.color === null
-      ? supported
+      ? color
       : options.color
   /** @type {Array<string>} */
   const lines = []

package.json

@@ -32,6 +32,9 @@
   "sideEffects": false,
   "type": "module",
   "main": "index.js",
+  "browser": {
+    "./lib/color.js": "./lib/color.browser.js"
+  },
   "types": "index.d.ts",
   "files": [
     "lib/",