better-stack-traces
v1.1.0
Published
Detailed stack traces with code snippets.
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Better Stack Traces
Ever find yourself digging line-by-line through a Javascript stack trace to find the "real" error?
Error: ENOENT, no such file or directory '/bad/file/path'
at Object.openSync (fs.js:230:18)
at Object.readFileSync (fs.js:120:15)
at readMyFile (/path/to/some/code/example.js:10:6)
at doStuff (/path/to/some/code/example.js:5:10)
at Object.<anonymous> (/path/to/some/code/example.js:13:1)
at Module._compile (module.js:441:26)
at Object..js (module.js:459:10)
at Module.load (module.js:348:31)
With better-stack-traces
, you get inline code snippets instead:
Error: ENOENT, no such file or directory '/bad/file/path'
at Object.openSync (fs.js:230:18)
at Object.readFileSync (fs.js:120:15)
at readMyFile (/path/to/some/code/example.js:10:6)
──────────────────────────────────────────────────
8 »
9 » function readMyFile(filePath) {
10 » fs.readFileSync(filePath);
•••••••••••
11 » }
12 »
13 » doStuff(readMyFile)
at doStuff (/path/to/some/code/example.js:5:10)
───────────────────────────────────────────────
3 »
4 » function doStuff(readCallback) {
5 » return readCallback("/bad/file/path");
••••••••••••••
6 » }
7 »
8 »
at Object.<anonymous> (/path/to/some/code/example.js:13:1)
──────────────────────────────────────────────────────────
11 » }
12 »
13 » doStuff(readMyFile)
••••••
at Module._compile (module.js:441:26)
at Object..js (module.js:459:10)
at Module.load (module.js:348:31)
Usage
- Install the module using
npm install better-stack-traces
- At the top of your code,
require("better-stack-traces").register()
- Alternatively,
require("better-stack-traces/register")
. This is useful for tools that have commandline options like--require
in mocha.
- Enjoy easier-to-read stack traces
Using better-stack-traces with CoffeeScript
If you develop with CoffeeScript,
better-stack-traces
will automatically compile .coffee
files when
rendering the trace. Maybe someday we will have
proper
line number mapping,
but until then better stack traces might help your sanity :)
Customizing the output
Stack traces not quite better enough? There are a few options to tweak the output:
require("better-stack-traces").register({
before: 2, // number of lines to show above the error
after: 3, // number of lines to show below the error
maxColumns: 80, // maximum number of columns to output in code snippets
collapseLibraries: /node_modules/ // omit code snippets from paths that match the given regexp (ignores node_modules by default)
})
If you want to get really fancy, take a look at the library itself. You can
subclass BetterStackTrace
and register your customized subclass instead.
Related resources
If you find better-stack-traces
useful, you might be interested in these:
- V8 Stack Trace API
- Tips for V8 stack formatting
- Long stack traces (for event handlers)
Contributors
- Wilker Lúcio (wilkerlucio)
- allow regex for
collapseLibraries
- allow regex for