Balanced brackets in JavaScript
JavaScript interview exercise on Practical, difficulty 3 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write isBalanced(str) that returns true when every (, [, { is closed by its matching bracket in the correct order. Other characters are ignored.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.