babakks / vscode-js-custom-breakpoint

A VS Code extension to set breakpoints at specific JavaScript call-stack locations

JS/TS Custom Breakpoint

This is a VS Code extension that lets you set breakpoints in JavaScript/TypeScript source codes that bound to their call-stack. This is a useful, when you're debugging complicated, highly-coupled, or recursive structures.

The extension does it's job by creating conditional breakpoints that check the stack trace to match the same trace at the time of setting the breakpoint.

⚠️ Currently, the extension only supports single-thread debug sessions.

Example use case

This is not a realistic use case, but serves the purpose here. Let's say in the code below you want to set a breakpoint on the return statement in the sayHello function. If you set an ordinary breakpoint, it'll hit by every call to sayHello (i.e., called by Caller 1, Caller 2, and Caller 3). But for some reason, you may only be interested in calls made by Caller 1 or Caller 2. So, you'd need a call-stack bound breakpoint, which only hits at the desired condition.

In a narrower case, you may just want to catch the calls only made by Caller 1. So, you'd need a strictly bound breakpoint which also binds to the location of the caller.

function sayHello() {
    return 'Hello!';  // Set a breakpoint here.
}

while (true) {
    sayHello(); // Caller 1
    sayHello(); // Caller 2
    (() => {
        sayHello(); // Caller 3
    })();
}

Set a call-stack bound breakpoint

To set a call-stack bound breakpoint, follow these steps:

1. Start the debugger, and stop at the stack frame you would want to set a bounded breakpoint.
2. Put the cursor on the line you want ot set the breakpoint on.
3. Either:
   1. Set a call-stack bound breakpoint by running Set Call-Stack Bound Breakpoint command (via pressing Ctrl+Shift+P and typing in the command name).
   2. Set a strictly bound breakpoint by running Set Call-Stack Bound Breakpoint (Strict) command (via pressing Ctrl+Shift+P and typing in the command name).
4. A new call-stack bound breakpoint will be set on the line at the cursor location.

Feedback

Please kindly provide your feedbacks through submitting issues/PRs in the extension's GitHub repository. 🍏