feat: hex color pattern

Author: mdjastrzebski

src/patterns/hex-color.ts

@@ -0,0 +1,40 @@
+import { buildRegExp } from '../builders';
+import { endOfString, startOfString } from '../constructs/anchors';
+import { charClass, charRange, digit } from '../constructs/character-class';
+import { choiceOf } from '../constructs/choice-of';
+import { optional } from '../constructs/quantifiers';
+import { repeat } from '../constructs/repeat';
+
+const hexDigit = charClass(digit, charRange('a', 'f'));
+
+/** Find hex color strings in a text. */
+export const hexColorFinder = buildRegExp(
+ [
+ '#',
+ choiceOf(
+ repeat(hexDigit, 6), // #rrggbb
+ repeat(hexDigit, 3), // #rgb
+ ),
+ ],
+ { ignoreCase: true },
+);
+
+/**
+ * Check that given text is a valid hex color.
+ *
+ * Allows both 3 and 6 digit hex colors, with or without the leading `#`.
+ * */
+export const hexColorValidator = buildRegExp(
+ [
+ startOfString, // Match whole string
+ optional('#'),
+ choiceOf(
+ repeat(hexDigit, 6), // #rrggbb
+ repeat(hexDigit, 3), // #rgb
+ ),
+ endOfString,
+ ],
+ {
+ ignoreCase: true,
+ },
+);

src/patterns/index.ts

@@ -0,0 +1 @@
+export { hexColorFinder, hexColorValidator } from './hex-color';