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Error constructor `after' support 

* lib/ctor/ErrorCtor.js (createCtor): Add `after' parameter to be
  invoked by `__$$ector$$__' at end of function.

* test/ctor/ErrorCtorTest.js: Add respective tests.
master
Mike Gerwitz 2016-06-26 00:28:21 -04:00
parent c69a42945c
commit d99ab2e5fb
No known key found for this signature in database
GPG Key ID: F22BB8158EE30EAB
2 changed files with 62 additions and 3 deletions
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18
lib/ctor/ErrorCtor.js
View File

@ -114,18 +114,28 @@ ErrorCtor.prototype = {
* classes, this will _not_ set up the prototype as a subtype of
* SUPERTYPE---the caller is expected to do so.
*
* @param {Function} supertype parent error constructor
* @param {string} name error subtype name
* AFTER, if provided, will be invoked at the end of the constructor;
* this allows the topmost frame to still be the error constructor,
* rather than having it wrapped to introduce additional logic.
*
* @param {Function} supertype parent error constructor
* @param {string} name error subtype name
* @param {?Function} after function to invoke after ctor
*
* @return {function(string)} error constructor
*/
createCtor: function( supertype, name )
createCtor: function( supertype, name, after )
{
if ( typeof supertype !== 'function' )
{
throw TypeError( "Expected constructor for supertype" );
}
if ( ( after !== undefined ) && ( typeof after !== 'function' ) )
{
throw TypeError( "Expected function as `after' argument" );
}
var _self = this;
// yes, this name is important, as we use it as an identifier for
@ -134,6 +144,8 @@ ErrorCtor.prototype = {
{
this.message = message;
_self._setStackTrace( this, _self._base, supertype );
after && after.apply( this, arguments );
}
// it's important to let the name fall through if not provided

47
test/ctor/ErrorCtorTest.js
View File

@ -507,4 +507,51 @@ require( 'common' ).testCase(
this.assertOk( !sut.isError( function() {} ) );
},
/**
* A function may optionally be provided to be invoked after the
* constructor has completed---this allows for the constructor to be
* augmented in such a way that the top stack frame is still the
* generated constructor when the error is instantiated.
*/
'Invokes provided function after self': function()
{
var called = false,
context = undefined,
argchk = {},
message = 'stillrunctor';
var result = new (
this.Sut( DummyError )
.createCtor( DummyError, '', function()
{
called = arguments;
context = this;
} )
)( message, argchk );
this.assertOk( called );
this.assertStrictEqual( argchk, called[ 1 ] );
this.assertStrictEqual( result, context );
// the ctor itself should also still be called (this depends on
// previous test also succeeding)
this.assertEqual( message, result.message );
},
/**
* Don't wait until instantiation to blow up on an invalid AFTER.
*/
'Throws error given a non-function `after\' argument': function()
{
var Sut = this.Sut;
this.assertThrows( function()
{
Sut( DummyError )
.createCtor( DummyError, '', "oops" );
}, TypeError );
},
} );