// Object.observe Example
myArray = [];
Object.observe(myArray, somethingChanged);
myArray[0]=100;
myArray[0]=200;
function somethingChanged(changes){
ForEach(changes, whatChanged)
}
function whatChanged(chnge) {
console.log(chnge.type, chnge.name, chnge.oldValue))
}
Object.observe: Difference between revisions
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Object.observe calls ''function'' whenever there is a change to ''object''. ''Object'' can be an array, collection, object, class or control. This can be very useful in debugging, to watch the value of an object change during runtime. Object.unobserve stops calling ''function''. | Object.observe calls ''function'' whenever there is a change to ''object''. ''Object'' can be an array, collection, object, class or control. This can be very useful in debugging, to watch the value of an object change during runtime. Object.unobserve stops calling ''function''. | ||
Important: This feature is only available in the Chrome browser, either on the desktop or on an Android device. | |||
== Example == | |||
<tabber> | |||
< | JavaScript= | ||
<syntaxhighlight lang="JavaScript"> | |||
// Object.observe Example | // Object.observe Example | ||
Line 40: | Line 27: | ||
console.log(chnge.type, chnge.name, chnge.oldValue)) | console.log(chnge.type, chnge.name, chnge.oldValue)) | ||
} | } | ||
</ | </syntaxhighlight> | ||
|-| | |||
BASIC= | |||
<syntaxhighlight lang="vb.net"> | |||
Rem Object.observe Example | |||
myArray = [] | |||
Object.observe(myArray, somethingChanged) | |||
myArray[0]=100 | |||
myArray[0]=200 | |||
Function somethingChanged(changes) | |||
ForEach(changes, whatChanged) | |||
End Function | |||
Function whatChanged(chnge) | |||
console.log(chnge.type, chnge.name, chnge.oldValue) | |||
End Function | |||
</syntaxhighlight> | |||
</tabber> | |||
== Output == | == Output == |
Latest revision as of 22:52, 24 July 2019
Object.observe(object, function) Object.unobserve(object)
Description
Object.observe calls function whenever there is a change to object. Object can be an array, collection, object, class or control. This can be very useful in debugging, to watch the value of an object change during runtime. Object.unobserve stops calling function.
Important: This feature is only available in the Chrome browser, either on the desktop or on an Android device.
Example
Rem Object.observe Example
myArray = []
Object.observe(myArray, somethingChanged)
myArray[0]=100
myArray[0]=200
Function somethingChanged(changes)
ForEach(changes, whatChanged)
End Function
Function whatChanged(chnge)
console.log(chnge.type, chnge.name, chnge.oldValue)
End Function
Output
add 0 undefined update length 0 update 0 100