[Solved] Why does this impure pipe cause performance issues?@Pipe({name: 'slowPipe', pure: false})export class SlowPipe implements PipeTransform { transform(value: any) { for(let i=0; i return value; }} | Angular

Angular - Pipes

Why does this impure pipe cause performance issues?

@Pipe({name: 'slowPipe', pure: false})
export class SlowPipe implements PipeTransform {
  transform(value: any) {
    for(let i=0; i<1000000; i++) {}
    return value;
  }
}

AIt does not implement PipeTransform correctly

BIt caches the result and never updates

CIt runs the expensive loop on every change detection cycle

DIt only runs once when the component loads

Step-by-Step Solution

Solution:

Step 1: Analyze impure pipe behavior
Impure pipes run on every change detection cycle.
Step 2: Identify expensive operation
The loop runs a million times each cycle, causing slow performance.
Final Answer:
It runs the expensive loop on every change detection cycle -> Option C
Quick Check:
Impure pipe + expensive code = slow app [OK]

Quick Trick: Avoid heavy work in impure pipes to prevent slowdowns [OK]

Common Mistakes:

Assuming impure pipes run once
Thinking result is cached
Believing PipeTransform is not implemented

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Why does this impure pipe cause performance issues?

Step 1: Analyze impure pipe behavior

Step 2: Identify expensive operation

Final Answer:

Quick Check:

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