hubcap errors - Capture JavaScript exceptions with stack traces

When to use

Capture JavaScript exceptions with full stack traces as they occur. Use console if you need all console messages including non-error output like log, warn, info, and debug.

Usage

hubcap errors [--duration <duration>]

Arguments

None.

Flags

Flag	Type	Default	Description
`--duration`	duration	`0`	How long to capture; 0 = until interrupted

Output

NDJSON stream written to stdout. Each line is a JSON object representing a JavaScript exception.

Field	Type	Description
`text`	string	Exception text
`lineNumber`	number	Line number of the exception
`columnNumber`	number	Column number of the exception
`url`	string	URL where the exception occurred

{"text":"TypeError: Cannot read properties of undefined (reading 'map')","lineNumber":42,"columnNumber":15,"url":"https://example.com/app.js"}

Errors

Condition	Exit code	Stderr
Chrome not connected	2	`error: connecting to Chrome: ...`
Timeout	3	`error: timeout`

Examples

Stream all JavaScript exceptions until Ctrl-C:

hubcap errors

Capture exceptions for 30 seconds:

hubcap errors --duration 30s

Count exceptions by message:

hubcap errors --duration 60s | jq -r '.message' | sort | uniq -c | sort -rn

Navigate to a page and check for errors:

hubcap goto --wait "https://example.com" && hubcap errors --duration 5s | jq -r '"[\(.text)]\n\(.url):\(.lineNumber)\n"'