JS RegExp Assertions
Assertions check a position without consuming a character. Anchors require the match to begin or end at a boundary.
Where to run this
This example uses the JavaScript console playground. Select Run to execute it; the example does not run on this lesson page.
A practical example
console.log(/^open$/i.test("OPEN"));
console.log(/^open$/i.test("open now"));
What happens
Only the whole-word input matches this anchored pattern.