Ignore 0xHHH and 0xHHHH hex colors

src/strategies/hex.js

@@ -1,6 +1,6 @@
 import Color from 'color';
 
-const colorHex = /.?((?:\#|\b0x)([a-f0-9]{6}([a-f0-9]{2})?|[a-f0-9]{3}([a-f0-9]{1})?))\b/gi;
+const colorHex = /.?((\#|\b0x)([a-f0-9]{6}([a-f0-9]{2})?|[a-f0-9]{3}([a-f0-9]{1})?))\b/gi;
 
 /**
  * @export
@@ -18,15 +18,24 @@ export async function findHex(text) {
   while (match !== null) {
     const firstChar = match[0][0];
     const matchedColor = match[1];
-    const matchedHex = '#' + match[2];
+    const colorPrefix = match[2];
+    const hexChars = match[3];
+
+    const matchedHex = '#' + hexChars;
     const start = match.index + (match[0].length - matchedColor.length);
     const end = colorHex.lastIndex;
 
-
-    // Check the symbol before the color match, and try to avoid coloring in the
-    // contexts that are not relevant
-    // https://github.com/sergiirocks/vscode-ext-color-highlight/issues/25
-    if (firstChar.length && /\w/.test(firstChar)) {
+    // We skip the match in the following cases:
+    // 1. If the symbol before the `#` (exists and) is a letter, to try to avoid
+    //    coloring in the contexts that are not relevant (such as inside a URL).
+    //    https://github.com/sergiirocks/vscode-ext-color-highlight/issues/25
+    const notRelevant = firstChar.length && /\w/.test(firstChar);
+    // 2. If the color is a numeric hex color, and it is only 3 or 4 characters
+    //    (e.g. `0xHHH` or `0xHHHH`), as these are *far* more likely to be
+    //    normal hexadecimal number literals, which do not represent a color.
+    const isShortNumeric = /0x/i.test(colorPrefix) && hexChars.length <= 4;
+
+    if (notRelevant || isShortNumeric) {
       match = colorHex.exec(text);
       continue;
     }

test/fixture/test.js

@@ -1,6 +1,6 @@
 // #f00
 // #ff0000
-// 0xf00
+// 0xff0000ff
 // 0xff0000
 // rgb(255, 0, 0)
 // rgb(100%, 0%, 0%)