balanced-parens

Balanced Parentheses

Background

When writing code, it's often nice to have an editor integration that will auto-generate a closing bracket for each open bracket you type. For instance, if you type {, your editor may actually print {} to the screen, with your cursor set between the two braces.

This is useful, but sometimes we accidentally delete a parenthesis or bracket or brace, and we want our editor to lint our code for such errors when they occur.

Balancing Parentheses

Today we're going to create a function that, given any string containing any arbitrary set of parentheses, brackets, or braces, can tell us if our parentheses are balanced (that is, there is a proper closing parenthesis for every opened parenthesis).

parensAreBalanced('([])') // true
parensAreBalanced('([)') // false

Careful though: not only do we need to make sure we have a balanced number of parentheses, but that they are also in the correct order. If we have ({, we want to make sure we see a closing } before a closing ).

Getting Started

The file you will be editing is balanced-parens.js.

The balanced-parens-test.js file includes a test suite to run your code against.

Run node balanced-parens-test.js to run the test suite in full. As you write code to pass tests, make sure you unskip succeeding tests by changing test.skip to just test.