# Observing a property whose name is dynamic

**URL:** <https://discuss.emberjs.com/t/observing-a-property-whose-name-is-dynamic/18146>\
**Category:** General\
**Created:** [August 20, 2020, 10:30am UTC](https://discuss.emberjs.com/t/observing-a-property-whose-name-is-dynamic/18146 "2020-08-20T10:30:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Moulidharan\_Rathinam](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/moulidharan_rathinam/32/16558_2.png) [@Moulidharan\_Rathinam](https://discuss.emberjs.com/u/Moulidharan_Rathinam)\
**Post date:** [August 20, 2020, 10:30am UTC](https://discuss.emberjs.com/t/observing-a-property-whose-name-is-dynamic/18146/1 "2020-08-20T10:30:29Z")

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Hi, I need to observe a property with a dynamic name (the name is computed from other properties).

`functionName: Ember.observer("string" + this.get("name"), function(){ <snippet>})`

unfortunately Ember can’t recognize “`this`” in the observer’s arguments.

I can’t find any references online regarding my use-case. Please help me on this!

Thank you.

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**Author:** ![Moulidharan\_Rathinam](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/moulidharan_rathinam/32/16558_2.png) [@Moulidharan\_Rathinam](https://discuss.emberjs.com/u/Moulidharan_Rathinam)\
**Post date:** [August 20, 2020, 1:12pm UTC](https://discuss.emberjs.com/t/observing-a-property-whose-name-is-dynamic/18146/2 "2020-08-20T13:12:28Z")

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Found a way to achieve this. I’ve used

> Ember.addObserver((“string” + this.get(“name”)), this, this.callBack);

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<div class="post-metadata">

**Author:** ![pzuraq](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/pzuraq/32/13754_2.png) [@pzuraq](https://discuss.emberjs.com/u/pzuraq)\
**Post date:** [August 26, 2020, 4:08pm UTC](https://discuss.emberjs.com/t/observing-a-property-whose-name-is-dynamic/18146/3 "2020-08-26T16:08:45Z")

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While it’s possible to add and remove observers dynamically, I definitely recommend against doing it, as observers are really non-performant and will eventually be removed from Ember. If you can provide some more details about what your observer does, I can try to help out with writing an alternative!