Move internal modules to “internal” folder.

.internal/unicodeToArray.js

@@ -0,0 +1,40 @@
+/** Used to compose unicode character classes. */
+const rsAstralRange = '\\ud800-\\udfff';
+const rsComboMarksRange = '\\u0300-\\u036f';
+const reComboHalfMarksRange = '\\ufe20-\\ufe2f';
+const rsComboSymbolsRange = '\\u20d0-\\u20ff';
+const rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange;
+const rsVarRange = '\\ufe0e\\ufe0f';
+
+/** Used to compose unicode capture groups. */
+const rsAstral = `[${ rsAstralRange }]`;
+const rsCombo = `[${ rsComboRange }]`;
+const rsFitz = '\\ud83c[\\udffb-\\udfff]';
+const rsModifier = `(?:${ rsCombo }|${ rsFitz })`;
+const rsNonAstral = `[^${ rsAstralRange }]`;
+const rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}';
+const rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]';
+const rsZWJ = '\\u200d';
+
+/** Used to compose unicode regexes. */
+const reOptMod = `${ rsModifier }?`;
+const rsOptVar = `[${ rsVarRange }]?`;
+const rsOptJoin = `(?:${ rsZWJ }(?:${ [rsNonAstral, rsRegional, rsSurrPair].join('|') })${ rsOptVar + reOptMod })*`;
+const rsSeq = rsOptVar + reOptMod + rsOptJoin;
+const rsSymbol = `(?:${ [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') })`;
+
+/** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
+const reUnicode = RegExp(`${ rsFitz }(?=${ rsFitz })|${ rsSymbol + rsSeq }`, 'g');
+
+/**
+ * Converts a Unicode `string` to an array.
+ *
+ * @private
+ * @param {string} string The string to convert.
+ * @returns {Array} Returns the converted array.
+ */
+function unicodeToArray(string) {
+  return string.match(reUnicode) || [];
+}
+
+export default unicodeToArray;