# Live Console Expression Evaluator Missing

**URL:** <https://discourse.mozilla.org/t/live-console-expression-evaluator-missing/43481>\
**Category:** Developer Tools\
**Created:** [August 6, 2019, 7:53pm UTC](https://discourse.mozilla.org/t/live-console-expression-evaluator-missing/43481 "2019-08-06T19:53:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![selman](https://avatars.discourse-cdn.com/v4/letter/s/fbc32d/32.png) [@selman](https://discourse.mozilla.org/u/selman)\
**Post date:** [August 6, 2019, 7:53pm UTC](https://discourse.mozilla.org/t/live-console-expression-evaluator-missing/43481/1 "2019-08-06T19:53:21Z")

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When typing expressions in the Console they are not evaluated live. this is a feature already available in chrome Dev tools, which is very useful…  
if for example i type in the following expression

> > document.querySelector(“.container-element”);

in chrome it will show the result of the evaluation (the first element with in this class) before pressing Enter, this has two benefits.

1. if you are typing long chained expressions, you can keep track of the result of each method call and property read.
2. if the expression is evaluated live then the return type will be known, this (if I’m not wrong) will enable Autocomplete when accessing Object returned by a function call directly on the function call.

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**Author:** ![digitarald](https://avatars.discourse-cdn.com/v4/letter/d/c77e96/32.png) [@digitarald](https://discourse.mozilla.org/u/digitarald)\
**Post date:** [August 6, 2019, 8:01pm UTC](https://discourse.mozilla.org/t/live-console-expression-evaluator-missing/43481/2 "2019-08-06T20:01:47Z")

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@selman we are also big fans of eager evaluation! It is definitely high on our list, but also needs a lot of coordination with the JS team to get it right. We have a bug [here](https://bugzilla.mozilla.org/show_bug.cgi?id=1460518) that you can follow.

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**Author:** ![selman](https://avatars.discourse-cdn.com/v4/letter/s/fbc32d/32.png) [@selman](https://discourse.mozilla.org/u/selman)\
**Post date:** [August 6, 2019, 8:15pm UTC](https://discourse.mozilla.org/t/live-console-expression-evaluator-missing/43481/3 "2019-08-06T20:15:12Z")

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So it’s called eager Evaluation… Thanks for the reply! hope it will be included soon…