https://github.com/rexxars/sourcemap-decorate-callsites

Decorate callsites with methods that return the sourcemapped file/line/column locations
https://github.com/rexxars/sourcemap-decorate-callsites

Last synced: 10 days ago
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Decorate callsites with methods that return the sourcemapped file/line/column locations

• Host: GitHub
• URL: https://github.com/rexxars/sourcemap-decorate-callsites
• Owner: rexxars
• License: mit
• Created: 2017-02-19T19:19:48.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2017-03-29T12:25:17.000Z (over 7 years ago)
• Last Synced: 2024-06-11T17:38:15.414Z (5 months ago)
• Language: JavaScript
• Size: 42 KB
• Stars: 1
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# sourcemap-decorate-callsites

[![Version npm](http://img.shields.io/npm/v/sourcemap-decorate-callsites.svg?style=flat-square)](http://browsenpm.org/package/sourcemap-decorate-callsites)[![Build Status](http://img.shields.io/travis/rexxars/sourcemap-decorate-callsites/master.svg?style=flat-square)](https://travis-ci.org/rexxars/sourcemap-decorate-callsites)

Decorate callsites with methods that return the sourcemapped file/line/column locations.  

Supports both file references and inline source maps.

## Installation

```bash

$ npm install --save sourcemap-decorate-callsites

```

## Usage

```js

var errorCallsites = require('error-callsites')

var decorateCallsites = require('sourcemap-decorate-callsites')

var someModule = require('some-module')

someModule.doAsyncThing(function (err) {

  if (!err) {

    return console.log('yaywin')

  }

  decorateCallsites(errorCallsites(err), function (sourcemapErr, callsites) {

    printCallsites(err, callsites)

  })

})

function printCallsites(err, callsites) {

  console.log('Error: %s', err.message)

  callsites.forEach(function (callsite) {

    console.log(

      '  in %s:%s:%s',

      callsite.getFileName(),

      callsite.getLineNumber(),

      callsite.getColumnNumber()

    )

  })

}

```

## How it works

* Passed callsites are resolved to filenames

* Filenames referenced are read from filesystem

* Source files are traversed, looking for references to a source map (`//# sourceMappingURL=some.js.map`)

* The source map is read from filesystem (or parsed from base64 in the case of inline source maps)

* A source map consumer is created using the [source-map](https://www.npmjs.com/package/source-map) module and cached in-memory

* The following functions for each callsite are modified to return the information from the source map if available:

  - `getFileName()`

  - `getLineNumber()`

  - `getColumnNumber()`

* When called, these functions will resolve the generated location to the original location based on the source map

## Notes

* To debug why a sourcemap can't be resolved or results in an error, you may pass `DEBUG=sourcemap-decorate-callsites` to your Node application, which will print debug info while resolving.

## License

MIT-licensed. See LICENSE.