thlorenz

Source Maps explained

Sourcemaps are becoming more and more part of our development stack and understanding them sooner or later is essential.

I'll give a quick run down on the following regarding source maps:

• how are they structured
• the different formats and how to encode/decode them
• where they are used (JavaScript transpilers, CSS transpilers, bundlers)
• how does the browser find and consumer source maps

thlorenz

from ubuntu:12.10

maintainer Thorsten Lorenz <thlorenz@gmx.de>

run apt-get update
run apt-get upgrade -y

run apt-get install -y build-essential

add . /src

thlorenz

from dockerfile/nodejs

add https://github.com/thlorenz/redeyed/archive/v0.4.4.tar.gz /src
workdir /src

entrypoint [ "npm" ]

thlorenz

/*
	Browserify Live Demos!
  How to make your own:
  1. Clone this RequireBin
  2. Adjust the REQUIRES section
  3. Create a gist with demo snippets that can be run
  4. Put the id for that gist into the demoGist variable
*/

/* REQUIRES: Put modules you need in your demo in this Array */

thlorenz

var d3Gauge = require('d3-gauge')
	, xtend = require('xtend')
	, insertCss = require('insert-css')

var gauges = [];
var small =  {
    size :  100
  , min  :  0
  , max  :  50 
  , transitionDuration : 500

thlorenz

Building lldb on Mac

Create Codesign Certificate

First we need to create a certificate. The llvm provided a way to do that, but I found this way to work slightly better for me. Just substitute lldb_codesign for the certificate name, instead of gdb-cert.

Install swig dependency

thlorenz

This is specifically tailored to Node.js binding projects in which case the C++ layer is always a library.

Clone gyp:

git clone --depth 1 https://chromium.googlesource.com/external/gyp.git gyp

Add the below common.gypi file in the root of the project.

thlorenz

perf list

pl-csv alias

Remove first 3 lines of perf list output and join the remaining ones together with ,

alias pl-csv='tail -n+3 | grep -v ^$ | awk '\''{print $1}'\'' | tr "\\n" "," | sed -e s/,$//'

thlorenz

pad > crypto.getHashes().length
46

pad > crypto.getCiphers().length
108

crypto.getHashes()
[ 'DSA',
  'DSA-SHA',
  'DSA-SHA1',

thlorenz

It is not usually recommended to reuse errors since the stack trace is attached whenever the error is instantiated.

However in some cases the overhead of doing that may affect performance, especially if the error is an exception that is known to occur frequently and is handled.

Only in these cases it may be advantagous to reuse the created Error. In all other cases getting a full stacktrace created at the time the exception occurs is to be preferred as it gives much better information needed to debug the problem.

Run

➝ node errors.js