[Solved] Identify the error in this Angular HTTP request code:const headers = new HttpHeaders(); headers.set('Content-Type', 'application/json'); this.http.post('/api/data', body, { headers }).subscribe(); | Angular

Angular - HTTP Client

Identify the error in this Angular HTTP request code:

const headers = new HttpHeaders();
headers.set('Content-Type', 'application/json');
this.http.post('/api/data', body, { headers }).subscribe();

AHeaders must be plain object, not HttpHeaders instance

BMissing import for HttpHeaders

CHttpHeaders is immutable; set() does not change original headers

Dpost() method requires params object

Step-by-Step Solution

Solution:

Step 1: Understand HttpHeaders immutability
HttpHeaders methods like set return new instances; original is unchanged.
Step 2: Analyze code behavior
Headers remain empty because set result is not assigned back.
Final Answer:
HttpHeaders is immutable; set() does not change original headers -> Option C
Quick Check:
HttpHeaders immutable = assign set() result [OK]

Quick Trick: Assign set() result to headers variable [OK]

Common Mistakes:

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