*ngFor iterate function are called many times

I’m submitting a…

[ ] Regression (a behavior that used to work and stopped working in a new release)
[X] Bug report  
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

Current behavior

for example, if you have a function that debugs a list, it is called several times when, theoretically, it should only be called once.

Expected behavior

https://stackblitz.com/edit/angular-ymxjt6?file=app%2Fapp.component.ts

Like a list should work in the service To only be called once to instantiate it.

Minimal reproduction of the problem with instructions

https://stackblitz.com/edit/angular-ymxjt6?file=app%2Fapp.component.ts

What is the motivation / use case for changing the behavior?

Environment

Angular version: X.Y.Z

Angular CLI: 1.6.1
Node: 8.0.0
OS: win32 x64
Angular: 5.1.1
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, platform-server, router

@angular/cdk: 5.0.1
@angular/cli: 1.6.1
@angular/material: 5.0.1
@angular/service-worker: 5.1.2
@angular-devkit/build-optimizer: 0.0.36
@angular-devkit/core: 0.0.22
@angular-devkit/schematics: 0.0.42
@ngtools/json-schema: 1.1.0
@ngtools/webpack: 1.9.1
@schematics/angular: 0.1.11
@schematics/schematics: 0.0.11
typescript: 2.4.2
webpack: 3.10.0

Browser:
- [x] Chrome (desktop) version XX
- [ ] Chrome (Android) version XX
- [ ] Chrome (iOS) version XX
- [ ] Firefox version XX
- [ ] Safari (desktop) version XX
- [ ] Safari (iOS) version XX
- [ ] IE version XX
- [ ] Edge version XX
 
For Tooling issues:
- Node version: XX  
- Platform:  

Others:

[mlc-mlapis]

@Phoenix404 Use trackBy and probably also OnPush strategy.

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