#stack-chain
API for combining call site modifyers
Installation
npm install stack-chain
API documentation
var chain = require('stack-chain');
When the Error.stack
getter is executed, the stack-chain
will perform the
following:
- execute the
modifiers
attached by chain.extend
. - execute the
modifiers
attached by chain.filter
. - execute the
formater
set by chain.format.replace
.
chain.extend.attach(modifier)
chain.filter.attach(modifier)
Will modify the callSite array. Note you shouldn't format the stack trace.
The modifier
is a function there takes two arguments error
and frames
.
error
is the Error
object.frames
is an array of callSite
objects, see
v8 documentation
for details.
When the modifier
is done, it should return
a modified frames
array.
chain.filter.attach(function (error, frames) {
var rewrite = frames.filter(function (callSite) {
return callSite.getFileName() !== module.filename;
});
return rewrite;
});
chain.extend.deattach(modifier)
chain.filter.deattach(modifier)
Removes a modifier
function from the list of modifiers
.
var modifier = function () {};
chain.extend.attach(modifier);
chain.extend.deattach(modifier);
chain.format.replace(formater)
Replaces the default v8 formater
. The new formater
takes a two arguments
error
and frames
.
error
is the Error
object.callSites
is an array of callSite
objects, see
v8 documentation
for details.
When the formater
is done, it should return
a string
. The string
will
what Error.stack
returns.
chain.format.replace(function (error, frames) {
var lines = [];
lines.push(error.toString());
for (var i = 0; i < frames.length; i++) {
lines.push(" at " + frames[i].toString());
}
return lines.join("\n");
});
chain.format.restore()
Will restore the default v8 formater
. Note that dude to the nature of v8
Error
objects, if one of the getters Error.stack
or Error.callSite
has
already executed, the value of Error.stack
won't change.
chain.callSite([options])
This will return the unmodified callSite
array from the current tick. This
is a performance shortcut, as it does not require generating the .stack
string. This behaviour is different from the Error().callSite
properties.
While this is mostly generating callSite
in hot code, it can be useful to
do some modification on the array. The options
object, supports the following:
options = {
extend: true,
filter: true,
slice: 2
}
Error.stackTraceLimit
This limites the size of the callSites
array. The default value is 10, and
can be set to any positive number including Infinity
. See
v8 documentation
for details.
Error().callSite.original
Returns the original callSite
array.
Error().callSite.mutated
Returns the mutated callSite
array, that is after extend
and filter
is applied. The array will not excite the Error.stackTraceLimit
.
License
The software is license under "MIT"
Copyright (c) 2012 Andreas Madsen
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.