Smalltalk current createPackage: 'Kernel-Objects' properties: #{}! nil subclass: #Object instanceVariableNames: '' category: 'Kernel-Objects'! !Object commentStamp! *Object is the root of the Smalltalk class system*. All classes in the system are subclasses of Object. Object provides default behavior common to all normal objects, such as: - access - copying - comparison - error handling - message sending - reflection Also utility messages that all objects should respond to are defined here. Object has no instance variable. ##Access Instance variables can be accessed with `#instVarAt:` and `#instVarAt:put:`. `Object >> instanceVariableNames` answers a collection of all instance variable names. Accessing JavaScript properties of an object is done through `#basicAt:`, `#basicAt:put:` and `basicDelete:`. ##Copying Copying an object is handled by `#copy` and `#deepCopy`. The first one performs a shallow copy of the receiver, while the second one performs a deep copy. The hook method `#postCopy` can be overriden in subclasses to copy fields as necessary to complete the full copy. It will be sent by the copy of the receiver. ##Comparison Objects understand equality `#=` and identity `#==` comparison. ##Error handling - `#halt` is the typical message to use for inserting breakpoints during debugging. - `#error:` throws a generic error exception - `#doesNotUnderstand:` handles the fact that there was an attempt to send the given message to the receiver but the receiver does not understand this message. Overriding this message can be useful to implement proxies for example.! !Object methodsFor: 'accessing'! yourself ^self ! class ! size self error: 'Object not indexable' ! instVarAt: aSymbol | varname | varname := aSymbol asString. ! instVarAt: aSymbol put: anObject | varname | varname := aSymbol asString. ! basicAt: aString ! basicAt: aString put: anObject ! basicDelete: aString ! identityHash ! ! !Object methodsFor: 'comparing'! = anObject ^self == anObject ! ~= anObject ^(self = anObject) = false ! == anObject ^self identityHash = anObject identityHash ! ~~ anObject ^(self == anObject) = false ! ! !Object methodsFor: 'converting'! -> anObject ^Association key: self value: anObject ! asString ^self printString ! asJavascript ^self asString ! asJSON ^JSON parse: self asJSONString ! asJSONString ^JSON stringify: self ! ! !Object methodsFor: 'copying'! copy ^self shallowCopy postCopy ! shallowCopy < var copy = self.klass._new(); for(var i in self) { if(/^@.+/.test(i)) { copy[i] = self[i]; } } return copy; > ! deepCopy < var copy = self.klass._new(); for(var i in self) { if(/^@.+/.test(i)) { copy[i] = self[i]._deepCopy(); } } return copy; > ! postCopy ! ! !Object methodsFor: 'error handling'! error: aString Error signal: aString ! subclassResponsibility self error: 'This method is a responsibility of a subclass' ! shouldNotImplement self error: 'This method should not be implemented in ', self class name ! try: aBlock catch: anotherBlock ! doesNotUnderstand: aMessage MessageNotUnderstood new receiver: self; message: aMessage; signal ! halt self error: 'Halt encountered' ! deprecatedAPI "Just a simple way to deprecate methods. #deprecatedAPI is in the 'error handling' protocol even if it doesn't throw an error, but it could in the future." console warn: thisContext home asString, ' is deprecated!! (in ', thisContext home home asString, ')' ! ! !Object methodsFor: 'initialization'! initialize ! ! !Object methodsFor: 'message handling'! perform: aSymbol ^self perform: aSymbol withArguments: #() ! perform: aSymbol withArguments: aCollection ^self basicPerform: aSymbol asSelector withArguments: aCollection ! basicPerform: aSymbol ^self basicPerform: aSymbol withArguments: #() ! basicPerform: aSymbol withArguments: aCollection ! ! !Object methodsFor: 'printing'! printString ^'a ', self class name ! printNl ! log: aString block: aBlock | result | console log: aString, ' time: ', (Date millisecondsToRun: [result := aBlock value]) printString. ^result ! storeString "Answer a String representation of the receiver from which the receiver can be reconstructed." ^ String streamContents: [:s | self storeOn: s] ! storeOn: aStream aStream nextPutAll: self printString ! ! !Object methodsFor: 'testing'! isKindOf: aClass ^(self isMemberOf: aClass) ifTrue: [true] ifFalse: [self class inheritsFrom: aClass] ! isMemberOf: aClass ^self class = aClass ! ifNil: aBlock "inlined in the Compiler" ^self ! ifNil: aBlock ifNotNil: anotherBlock "inlined in the Compiler" ^anotherBlock value ! ifNotNil: aBlock "inlined in the Compiler" ^aBlock value ! ifNotNil: aBlock ifNil: anotherBlock "inlined in the Compiler" ^aBlock value ! isNil ^false ! notNil ^self isNil not ! isClass ^false ! isMetaclass ^false ! isNumber ^false ! isString ^false ! isParseFailure ^false ! isSymbol ^false ! ! !Object class methodsFor: 'initialization'! initialize "no op" ! ! Object subclass: #Smalltalk instanceVariableNames: '' category: 'Kernel-Objects'! !Smalltalk commentStamp! Smalltalk has only one instance, accessed with `Smalltalk current`. It represents the global JavaScript variable `smalltalk` declared in `js/boot.js`. The `smalltalk` object holds all class and packages defined in the system. ## Classes Classes can be accessed using the following methods: - `#classes` answers the full list of Smalltalk classes in the system - `#at:` answers a specific class of `nil` ## Packages Packages can be accessed using the following methods: - `#packages` answers the full list of packages - `#packageAt:` answers a specific class of `nil` __note:__ classes and packages are accessed using strings, not symbols ## Parsing The `#parse:` method is used to parse Smalltalk source code. It requires the `Compiler` package and the `js/parser.js` parser file in order to work! !Smalltalk methodsFor: 'accessing'! classes ! at: aString ! basicParse: aString ! parse: aString | result | self try: [result := self basicParse: aString] catch: [:ex | (self parseError: ex parsing: aString) signal]. ^result ! parseError: anException parsing: aString | row col message lines badLine code | . lines := aString lines. badLine := lines at: row. badLine := (badLine copyFrom: 1 to: col - 1), ' ===>', (badLine copyFrom: col to: badLine size). lines at: row put: badLine. code := String streamContents: [:s | lines withIndexDo: [:l :i | s nextPutAll: i asString, ': ', l, String lf]]. ^ Error new messageText: ('Parse error on line ' , row , ' column ' , col , ' : ' , message , ' Below is code with line numbers and ===> marker inserted:' , String lf, code) ! reservedWords "JavaScript reserved words" ! readJSObject: anObject ! ! !Smalltalk methodsFor: 'classes'! removeClass: aClass aClass isMetaclass ifTrue: [self error: aClass asString, ' is a Metaclass and cannot be removed!!']. aClass methodDictionary values do: [:each | aClass removeCompiledMethod: each]. aClass class methodDictionary values do: [:each | aClass class removeCompiledMethod: each]. self basicDelete: aClass name ! ! !Smalltalk methodsFor: 'packages'! packages "Return all Package instances in the system." ! packageAt: packageName ! packageAt: packageName ifAbsent: aBlock ^(self packageAt: packageName) ifNil: aBlock ! removePackage: packageName "Removes a package and all its classes." | pkg | pkg := self packageAt: packageName ifAbsent: [self error: 'Missing package: ', packageName]. pkg classes do: [:each | self removeClass: each]. self deletePackage: packageName ! renamePackage: packageName to: newName "Rename a package." | pkg | pkg := self packageAt: packageName ifAbsent: [self error: 'Missing package: ', packageName]. (self packageAt: newName) ifNotNil: [self error: 'Already exists a package called: ', newName]. . pkg name: newName. self deletePackage: packageName. ! ! !Smalltalk methodsFor: 'private'! createPackage: packageName "Create and bind a new package with given name and return it." ! deletePackage: packageName "Deletes a package by deleting its binding, but does not check if it contains classes etc. To remove a package, use #removePackage instead." ! createPackage: packageName properties: aDict "Create and bind a new package with given name and return it." | object | . aDict keysAndValuesDo: [:key :value | . ]. ! ! Smalltalk class instanceVariableNames: 'current'! !Smalltalk class methodsFor: 'accessing'! current ! ! Object subclass: #Package instanceVariableNames: 'commitPathJs commitPathSt' category: 'Kernel-Objects'! !Package commentStamp! A Package is similar to a "class category" typically found in other Smalltalks like Pharo or Squeak. Amber does not have class categories anymore, it had in the beginning but now each class in the system knows which package it belongs to. A Package has a name, an Array of "requires", a comment and a Dictionary with other optional key value attributes. A Package can also be queried for its classes, but it will then resort to a reverse scan of all classes to find them. Packages are manipulated through "Smalltalk current", like for example finding one based on a name: Smalltalk current packageAt: 'Kernel' ...but you can also use: Package named: 'Kernel' A Package differs slightly from a Monticello package which can span multiple class categories using a naming convention based on hyphenation. But just as in Monticello a Package supports "class extensions" so a Package can define behaviors in foreign classes using a naming convention for method categories where the category starts with an asterisk and then the name of the owning package follows. This can easily be seen in for example class String where the method category "*IDE" defines #inspectOn: which thus is a method belonging to the IDE package. You can fetch a package from the server: Package fetch: 'Additional-Examples'! !Package methodsFor: 'accessing'! name ! name: aString ! dependencies ^self propertyAt: 'dependencies' ifAbsent: [#()] ! dependencies: anArray ^self propertyAt: 'dependencies' put: anArray ! properties ^Smalltalk current readJSObject: (self basicAt: 'properties') ! properties: aDict "We store it as a javascript object." | object | . aDict keysAndValuesDo: [:key :value | . ]. ! commitPathJs ^ commitPathJs ifNil: [self class defaultCommitPathJs] ! commitPathJs: aString commitPathJs := aString ! commitPathSt ^ commitPathSt ifNil: [self class defaultCommitPathSt] ! commitPathSt: aString commitPathSt := aString ! ! !Package methodsFor: 'classes'! classes "We need to do a reverse scan." ^Smalltalk current classes select: [:c | c package == self] ! ! !Package methodsFor: 'printing'! printString ^self name ! ! !Package methodsFor: 'private'! propertiesAsJSON ! jsProperties ! jsProperties: aJSObject ! ! !Package methodsFor: 'properties'! propertyAt: key ! propertyAt: key put: value ! propertyAt: key ifAbsent: block ^(self propertyAt: key) ifNil: [block value] ! ! Package class instanceVariableNames: 'defaultCommitPathJs defaultCommitPathSt'! !Package class methodsFor: 'commit paths'! defaultCommitPathJs ^ defaultCommitPathJs ifNil: [ defaultCommitPathJs := 'js'] ! defaultCommitPathJs: aString defaultCommitPathJs := aString ! defaultCommitPathSt ^ defaultCommitPathSt ifNil: [ defaultCommitPathSt := 'st'] ! defaultCommitPathSt: aString defaultCommitPathSt := aString ! resetCommitPaths defaultCommitPathJs := nil. defaultCommitPathSt := nil. ! ! !Package class methodsFor: 'loading-storing'! fetch: aPackageName prefix: aPrefix jQuery getScript: (aPrefix , aPackageName , '.js') onSuccess: [ Package init: aPackageName ] ! fetch: aPackageName self fetch: aPackageName prefix: self defaultCommitPathJs, '/' ! commitToLocalStorage: aPackageName | key sourceCode | key := 'smalltalk.packages.' , aPackageName. sourceCode := Exporter new exportPackage: aPackageName. ! init: aPackageName (smalltalk classes select: [ :each | ]) do: [ :each | ]; do: [ :each | each initialize ] ! ! !Package class methodsFor: 'not yet classified'! named: aPackageName ^Smalltalk current packageAt: aPackageName ! named: aPackageName ifAbsent: aBlock ^Smalltalk current packageAt: aPackageName ifAbsent: aBlock ! ! Object subclass: #Number instanceVariableNames: '' category: 'Kernel-Objects'! !Number commentStamp! Number holds the most general methods for dealing with numbers. Number is directly mapped to JavaScript Number. Most arithmetic methods like `#+` `#/` `#-` `#max:` are directly inlined into javascript. ##Enumerating A Number can be used to evaluate a Block a fixed number of times: 5 timesRepeat: [Transcript show: 'This will be printed 5 times'; cr]. 1 to: 5 do: [:aNumber| Transcript show: aNumber asString; cr]. 1 to: 10 by: 2 do: [:aNumber| Transcript show: aNumber asString; cr].! !Number methodsFor: ''! ! ! !Number methodsFor: 'accessing'! identityHash ^self asString, 'n' ! ! !Number methodsFor: 'arithmetic'! + aNumber "Inlined in the Compiler" ! - aNumber "Inlined in the Compiler" ! * aNumber "Inlined in the Compiler" ! / aNumber "Inlined in the Compiler" ! max: aNumber ! min: aNumber ! negated ^0 - self ! \\ aNumber ! sqrt ! squared ^self * self ! ! !Number methodsFor: 'comparing'! = aNumber aNumber isNumber ifFalse: [^false]. ! > aNumber "Inlined in the Compiler" > aNumber> ! < aNumber "Inlined in the Compiler" ! >= aNumber "Inlined in the Compiler" >= aNumber> ! <= aNumber "Inlined in the Compiler" ! ! !Number methodsFor: 'converting'! rounded ! truncated |result| self >= 0 ifTrue: [] ifFalse: []. ^ result ! to: aNumber | array first last count | first := self truncated. last := aNumber truncated + 1. count := 1. array := Array new. (last - first) timesRepeat: [ array at: count put: first. count := count + 1. first := first + 1]. ^array ! asString ^self printString ! asJavascript ^'(', self printString, ')' ! atRandom ^(Random new next * self) truncated + 1 ! @ aNumber ^Point x: self y: aNumber ! asPoint ^Point x: self y: self ! to: stop by: step | array value pos | value := self. array := Array new. pos := 1. step = 0 ifTrue: [self error: 'step must be non-zero']. step < 0 ifTrue: [[ value >= stop ] whileTrue: [ array at: pos put: value. pos := pos + 1. value := value + step]] ifFalse: [[ value <= stop ] whileTrue: [ array at: pos put: value. pos := pos + 1. value := value + step]]. ^array ! ! !Number methodsFor: 'copying'! deepCopy ^self copy ! copy ^self ! ! !Number methodsFor: 'enumerating'! timesRepeat: aBlock | integer count | integer := self truncated. count := 1. [count > self] whileFalse: [ aBlock value. count := count + 1] ! to: stop do: aBlock "Evaluate aBlock for each number from self to aNumber." | nextValue | nextValue := self. [nextValue <= stop] whileTrue: [aBlock value: nextValue. nextValue := nextValue + 1] ! to: stop by: step do: aBlock | value | value := self. step = 0 ifTrue: [self error: 'step must be non-zero']. step < 0 ifTrue: [[ value >= stop ] whileTrue: [ aBlock value: value. value := value + step]] ifFalse: [[ value <= stop ] whileTrue: [ aBlock value: value. value := value + step]] ! ! !Number methodsFor: 'printing'! printString ! printShowingDecimalPlaces: placesDesired ! ! !Number methodsFor: 'testing'! isNumber ^true ! even ^ 0 = (self \\ 2) ! odd ^ self even not ! negative "Answer whether the receiver is mathematically negative." ^ self < 0 ! positive "Answer whether the receiver is positive or equal to 0. (ST-80 protocol)." ^ self >= 0 ! isZero ^self = 0 ! ! !Number methodsFor: 'timeouts/intervals'! clearInterval ! clearTimeout ! ! !Number class methodsFor: 'instance creation'! pi ! ! Object subclass: #Boolean instanceVariableNames: '' category: 'Kernel-Objects'! !Boolean commentStamp! Boolean wraps the JavaScript `Boolean()` constructor. The `true` and `false` objects are the JavaScript boolean objects. Boolean defines the protocol for logic testing operations and conditional control structures for the logical values. Boolean instances are weither `true` or `false`.! !Boolean methodsFor: 'comparing'! = aBoolean aBoolean class = self class ifFalse: [^false]. ! ! !Boolean methodsFor: 'controlling'! ifTrue: aBlock "inlined in the Compiler" ^self ifTrue: aBlock ifFalse: [] ! ifFalse: aBlock "inlined in the Compiler" ^self ifTrue: [] ifFalse: aBlock ! ifFalse: aBlock ifTrue: anotherBlock "inlined in the Compiler" ^self ifTrue: anotherBlock ifFalse: aBlock ! ifTrue: aBlock ifFalse: anotherBlock "inlined in the Compiler" < if(self == true) { return aBlock(); } else { return anotherBlock(); } > ! and: aBlock ^self = true ifTrue: aBlock ifFalse: [false] ! or: aBlock ^self = true ifTrue: [true] ifFalse: aBlock ! not ^self = false ! & aBoolean < if(self == true) { return aBoolean; } else { return false; } > ! | aBoolean < if(self == true) { return true; } else { return aBoolean; } > ! ! !Boolean methodsFor: 'copying'! shallowCopy ^self ! deepCopy ^self ! ! !Boolean methodsFor: 'printing'! printString ! ! Object subclass: #Date instanceVariableNames: '' category: 'Kernel-Objects'! !Date commentStamp! The Date class is used to work with dates and times. Therefore `Date today` and `Date now` are both valid in Amber and answer the same date object. Date wraps the `Date()` JavaScript constructor, and Smalltalk date objects are JavaScript date objects.! !Date methodsFor: 'accessing'! year ! month ! month: aNumber ! day ^self dayOfWeek ! dayOfWeek ! dayOfWeek: aNumber ! day: aNumber self day: aNumber ! year: aNumber ! dayOfMonth ! dayOfMonth: aNumber ! time ! time: aNumber ! hours: aNumber ! minutes: aNumber ! seconds: aNumber ! milliseconds: aNumber ! hours ! minutes ! seconds ! milliseconds ! ! !Date methodsFor: 'arithmetic'! - aDate ! + aDate ! ! !Date methodsFor: 'comparing'! < aDate ! > aDate > aDate> ! <= aDate ! >= aDate >= aDate> ! ! !Date methodsFor: 'converting'! asString ! asMilliseconds ^self time ! asDateString ! asTimeString ! asLocaleString ! asNumber ^self asMilliseconds ! ! !Date methodsFor: 'printing'! printString ^self asString ! ! !Date class methodsFor: 'instance creation'! new: anObject ! fromString: aString "Example: Date fromString('2011/04/15 00:00:00')" ^self new: aString ! fromSeconds: aNumber ^self fromMilliseconds: aNumber * 1000 ! fromMilliseconds: aNumber ^self new: aNumber ! today ^self new ! now ^self today ! millisecondsToRun: aBlock | t | t := Date now. aBlock value. ^Date now - t ! ! Object subclass: #UndefinedObject instanceVariableNames: '' category: 'Kernel-Objects'! !UndefinedObject commentStamp! UndefinedObject describes the behavior of its sole instance, `nil`. `nil` represents a prior value for variables that have not been initialized, or for results which are meaningless. `nil` is the Smalltalk representation of the `undefined` JavaScript object.! !UndefinedObject methodsFor: 'class creation'! subclass: aString instanceVariableNames: anotherString ^self subclass: aString instanceVariableNames: anotherString package: nil ! subclass: aString instanceVariableNames: aString2 category: aString3 "Kept for compatibility." self deprecatedAPI. ^self subclass: aString instanceVariableNames: aString2 package: aString3 ! subclass: aString instanceVariableNames: aString2 package: aString3 ^ClassBuilder new superclass: self subclass: aString instanceVariableNames: aString2 package: aString3 ! ! !UndefinedObject methodsFor: 'copying'! shallowCopy ^self ! deepCopy ^self ! ! !UndefinedObject methodsFor: 'printing'! printString ^'nil' ! ! !UndefinedObject methodsFor: 'testing'! ifNil: aBlock "inlined in the Compiler" ^self ifNil: aBlock ifNotNil: [] ! ifNotNil: aBlock "inlined in the Compiler" ^self ! ifNil: aBlock ifNotNil: anotherBlock "inlined in the Compiler" ^aBlock value ! ifNotNil: aBlock ifNil: anotherBlock "inlined in the Compiler" ^anotherBlock value ! isNil ^true ! notNil ^false ! ! !UndefinedObject class methodsFor: 'instance creation'! new self error: 'You cannot create new instances of UndefinedObject. Use nil' ! ! Object subclass: #Random instanceVariableNames: '' category: 'Kernel-Objects'! !Random commentStamp! `Random` is a random number generator and is implemented as a trivial wrapper around javascript `Math.random()` and is used like this: Random new next This will return a float x where x < 1 and x > 0. If you want a random integer from 1 to 10 you can use `#atRandom` 10 atRandom ...and if you want a random number in a specific interval this also works: (3 to: 7) atRandom ...but be aware that `#to:` does not create an Interval as in other Smalltalk implementations but in fact an `Array` of numbers, so it's better to use: 5 atRandom + 2 Since `#atRandom` is implemented in `SequencableCollection` you can easy pick an element at random: #('a' 'b' 'c') atRandom ...or perhaps a letter from a `String`: 'abc' atRandom Since Amber does not have Characters this will return a `String` of length 1 like for example `'b'`.! !Random methodsFor: 'accessing'! next ! next: anInteger ^(1 to: anInteger) collect: [:each | self next] ! ! Object subclass: #Point instanceVariableNames: 'x y' category: 'Kernel-Objects'! !Point commentStamp! A `Point` represents an x-y pair of numbers usually designating a geometric coordinate. Points are traditionally created using the binary `#@` message to a number: 100@120 Points can then be arithmetically manipulated: 100@100 + (10@10) ...or for example: (100@100) * 2 **NOTE:** Creating a Point with a negative y-value will need a space after `@` in order to avoid a parsing error: 100@ -100 "but 100@-100 would not parse" Amber does not have much behavior in this class out-of-the-box.! !Point methodsFor: 'accessing'! x ^x ! y ^y ! y: aNumber y := aNumber ! x: aNumber x := aNumber ! ! !Point methodsFor: 'arithmetic'! * aPoint ^Point x: self x * aPoint asPoint x y: self y * aPoint asPoint y ! + aPoint ^Point x: self x + aPoint asPoint x y: self y + aPoint asPoint y ! - aPoint ^Point x: self x - aPoint asPoint x y: self y - aPoint asPoint y ! / aPoint ^Point x: self x / aPoint asPoint x y: self y / aPoint asPoint y ! = aPoint ^aPoint class = self class and: [ (aPoint x = self x) & (aPoint y = self y)] ! ! !Point methodsFor: 'converting'! asPoint ^self ! ! !Point methodsFor: 'printing'! printString "Print receiver in classic x@y notation." ^String streamContents: [:stream | stream nextPutAll: x printString, '@'. (y notNil and: [y negative]) ifTrue: [ "Avoid ambiguous @- construct" stream space]. stream nextPutAll: y printString] ! ! !Point class methodsFor: 'instance creation'! x: aNumber y: anotherNumber ^self new x: aNumber; y: anotherNumber; yourself ! ! Object subclass: #JSObjectProxy instanceVariableNames: 'jsObject' category: 'Kernel-Objects'! !JSObjectProxy commentStamp! JSObjectProxy handles sending messages to JavaScript object, therefore accessing JavaScript objects from Amber is transparent. JSOjbectProxy makes intensive use of `#doesNotUnderstand:`. ## Examples JSObjectProxy objects are instanciated by Amber when a Smalltalk message is sent to a JavaScript object. window alert: 'hello world'. window inspect. (window jQuery: 'body') append: 'hello world' Smalltalk messages sends are converted to JavaScript function calls or object property access _(in this order)_. If n one of them match, a `MessageNotUnderstood` error will be thrown. ## Message conversion rules - `someUser name` becomes `someUser.name` - `someUser name: 'John'` becomes `someUser name = "John"` - `console log: 'hello world'` becomes `console.log('hello world')` - `(window jQuery: 'foo') css: 'background' color: 'red'` becomes `window.jQuery('foo').css('background', 'red')` __Note:__ For keyword-based messages, only the first keyword is kept: `window foo: 1 bar: 2` is equivalent to `window foo: 1 baz: 2`.! !JSObjectProxy methodsFor: 'accessing'! jsObject: aJSObject jsObject := aJSObject ! jsObject ^jsObject ! at: aSymbol | attr | attr := aSymbol asString. ! at: aSymbol put: anObject | attr | attr := aSymbol asString. ! ! !JSObjectProxy methodsFor: 'proxy'! printString ^self jsObject toString ! inspectOn: anInspector | variables | variables := Dictionary new. variables at: '#self' put: self jsObject. anInspector setLabel: self printString. . anInspector setVariables: variables ! doesNotUnderstand: aMessage | obj selector jsSelector arguments | obj := self jsObject. selector := aMessage selector. jsSelector := selector asJavaScriptSelector. arguments := aMessage arguments. . super doesNotUnderstand: aMessage ! ! !JSObjectProxy class methodsFor: 'instance creation'! on: aJSObject ^self new jsObject: aJSObject; yourself ! !