How to check empty object in angular 2 template using *ngIf

Question

I want to check if my object is empty dont render my element, and this is my code:

Answer 1

From the above answeres, following did not work or less preferable:

• (previous_info | json) != '{}' works only for {} empty case, not for null or undefined case
• Object.getOwnPropertyNames(previous_info).length also did not work, as Object is not accessible in the template
• I would not like to create a dedicated variable this.objectLength = Object.keys(this.previous_info).length !=0;

• I would not like to create a dedicated function

  isEmptyObject(obj) {
     return (obj && (Object.keys(obj).length === 0));
  }
  

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Solution: keyvalue pipe along with ?. (safe navigation operator); and it seems simple.

It works well when previous_info = null or previous_info = undefined or previous_info = {} and treats as falsy value.

keyvalue - Transforms Object or Map into an array of key value pairs.

?. - The Angular safe navigation operator (?.) is a fluent and convenient way to guard against null and undefined

DEMO: demo with angular 9, though it works for previous versions as well