feat: minor performance improvement

index.js

@@ -96,11 +96,11 @@ export function relativeToDate(expression, currentDate = new Date()) {
     throw new TypeError('The expression should be a string');
   }
 
-  if (!isValid(expression)) {
+  const match = expression.match(regExp);
+  if (!match) {
     throw new Error('The expression is not a valid expression');
   }
 
-  const match = expression.match(regExp);
   const operator = match[1] === '-' ? -1 : 1;
   const amount = parseInt(match[2]);
   const unit = units[match[3]];

index.test.js

@@ -1,6 +1,6 @@
 import assert from 'node:assert';
 import { describe, it } from 'node:test';
-import { relativeToDate } from './index.js';
+import { isValid, relativeToDate } from './index.js';
 
 describe('datelative', () => {
   describe('Invalid expressions', () => {
@@ -111,6 +111,8 @@ describe('datelative', () => {
       it(expression, () => {
         const reference = new Date();
         const expected = new Date(reference.getTime() + millis);
+
+        assert.deepEqual(isValid(expression), true);
         assert.deepEqual(relativeToDate(expression, reference), expected);
       });
     });

package.json

@@ -1,6 +1,6 @@
 {
   "name": "datelative",
-  "version": "0.0.6",
+  "version": "0.0.7",
   "description": "A library that converts relative string text to JavaScript dates",
   "type": "module",