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jakesgordonjakesgordon
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extend the custom error handler (cfg.error) to support handling the case where a caller provided callback throws an exception
NOTE: I'm not entirely happy with this direction, I'm not sure if this will ever make it onto the master branch - see comments in github issue jakesgordon#3
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‎README.md‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
Javascript Finite State Machine (v2.0.0)
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Javascript Finite State Machine (v2.0.1)
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========================================
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This standalone javascript micro-framework provides a finite state machine for your pleasure.

‎RELEASE_NOTES.md‎

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@@ -1,3 +1,10 @@
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Version 2.0.1 (unreleased)
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--------------------------
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* extended custom error callback to handle any exceptions caused by caller provided callbacks
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* added custom error callback to override exception when an illegal state transition is attempted (thanks to cboone)
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* fixed typos (thanks to cboone)
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* fixed issue #4 - ensure before/after event hooks are called even if the event doesn't result in a state change
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Version 2.0.0 (August 19th 2011)
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--------------------------------

‎state-machine.js‎

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Original file line numberDiff line numberDiff line change
@@ -2,7 +2,7 @@ StateMachine = {
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//---------------------------------------------------------------------------
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5-
VERSION: "2.0.0",
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VERSION: "2.0.1",
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//---------------------------------------------------------------------------
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@@ -31,7 +31,7 @@ StateMachine = {
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for(var name in map) {
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if (map.hasOwnProperty(name))
34-
fsm[name] = StateMachine.buildEvent(name, map[name], cfg.error);
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fsm[name] = StateMachine.buildEvent(name, map[name]);
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}
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for(var name in callbacks) {
@@ -43,6 +43,7 @@ StateMachine = {
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fsm.is = function(state) { return this.current == state; };
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fsm.can = function(event) { return !!map[event][this.current] && !this.transition; };
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fsm.cannot = function(event) { return !this.can(event); };
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fsm.error = cfg.error || function(eventName, error) { throw error; };
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if (initial && !initial.defer)
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fsm[initial.event]();
@@ -53,77 +54,60 @@ StateMachine = {
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//===========================================================================
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56-
beforeEvent: function(name, from, to, args) {
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var func = this['onbefore' + name];
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if (func)
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return func.apply(this, [name, from, to].concat(args));
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},
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afterEvent: function(name, from, to, args) {
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var func = this['onafter' + name] || this['on' + name];
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if (func)
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return func.apply(this, [name, from, to].concat(args));
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},
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leaveState: function(name, from, to, args) {
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var func = this['onleave' + from];
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if (func)
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return func.apply(this, [name, from, to].concat(args));
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doCallback: function(fsm, func, name, from, to, args) {
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if (func) {
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try {
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return func.apply(fsm, [name, from, to].concat(args));
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}
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catch(e) {
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fsm.error(name, e);
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}
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}
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},
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74-
enterState: function(name, from, to, args) {
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var func = this['onenter' + to] || this['on' + to];
76-
if (func)
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return func.apply(this, [name, from, to].concat(args));
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},
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beforeEvent: function(fsm, name, from, to, args) { return StateMachine.doCallback(fsm, fsm['onbefore' + name], name, from, to, args); },
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afterEvent: function(fsm, name, from, to, args) { return StateMachine.doCallback(fsm, fsm['onafter' + name] || fsm['on' + name], name, from, to, args); },
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leaveState: function(fsm, name, from, to, args) { return StateMachine.doCallback(fsm, fsm['onleave' + from], name, from, to, args); },
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enterState: function(fsm, name, from, to, args) { return StateMachine.doCallback(fsm, fsm['onenter' + to] || fsm['on' + to], name, from, to, args); },
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changeState: function(fsm, name, from, to, args) { return StateMachine.doCallback(fsm, fsm['onchangestate'], name, from, to, args); },
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changeState: function(name, from, to, args) {
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var func = this['onchangestate'];
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if (func)
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return func.apply(this, [name, from, to].concat(args));
84-
},
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86-
buildEvent: function(name, map, errorHandler) {
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buildEvent: function(name, map) {
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return function() {
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if (this.transition)
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throw "event " + name + " inappropriate because previous transition did not complete"
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return this.error(name, "event " + name + " inappropriate because previous transition did not complete");
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92-
if (this.cannot(name)) {
93-
if (errorHandler) {
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return errorHandler.call(this, name);
95-
} else {
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throw "event " + name + " inappropriate in current state " + this.current;
97-
}
98-
}
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if (this.cannot(name))
82+
return this.error(name, "event " + name + " inappropriate in current state " + this.current);
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var from = this.current;
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var to = map[from];
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var args = Array.prototype.slice.call(arguments); // turn arguments into pure array
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104-
if (false === StateMachine.beforeEvent.call(this, name, from, to, args))
88+
if (false === StateMachine.beforeEvent(this, name, from, to, args))
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return;
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10791
if (from !== to) {
10892

109-
var self = this;
93+
var fsm = this;
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this.transition = function() { // prepare transition method for use either lower down, or by caller if they want an async transition (indicated by a false return value from leaveState)
111-
self.transition = null; // this method should only ever be called once
112-
self.current = to;
113-
StateMachine.enterState.call( self, name, from, to, args);
114-
StateMachine.changeState.call(self, name, from, to, args);
115-
StateMachine.afterEvent.call( self, name, from, to, args);
95+
fsm.transition = null; // this method should only ever be called once
96+
fsm.current = to;
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StateMachine.enterState( fsm, name, from, to, args);
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StateMachine.changeState(fsm, name, from, to, args);
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StateMachine.afterEvent( fsm, name, from, to, args);
116100
};
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118-
if (false !== StateMachine.leaveState.call(this, name, from, to, args)) {
102+
if (false !== StateMachine.leaveState(this, name, from, to, args)) {
119103
if (this.transition) // in case user manually called it but forgot to return false
120104
this.transition();
121105
}
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123107
return; // transition method took care of (or, if async, will take care of) the afterEvent, DONT fall through
124108
}
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126-
StateMachine.afterEvent.call(this, name, from, to, args); // this is only ever called if there was NO transition (e.g. if from === to)
110+
StateMachine.afterEvent(this, name, from, to, args); // this is only ever called if there was NO transition (e.g. if from === to)
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128112
};
129113
}

‎state-machine.min.js‎

Lines changed: 1 addition & 1 deletion
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‎test/test_basics.js‎

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@@ -151,9 +151,7 @@ test("inappropriate events", function() {
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test("inappropriate event handling can be customized", function() {
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var fsm = StateMachine.create({
154-
error: function(eventName) {
155-
return 'event ' + eventName + ' inappropriate in current state ' + this.current;
156-
},
154+
error: function(eventName, message) { return message; }, // return error message instead of throwing an exception
157155
initial: 'green',
158156
events: [
159157
{ name: 'warn', from: 'green', to: 'yellow' },

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