manual-iterator-inspect

Prefer Iterator.inspect when mapping observes and returns each value

Mapping an iterator value only to observe it before returning it unchanged obscures the side effect.
Instead, you SHOULD call inspect to observe each value without changing the sequence.

- Category: style
- Level: warning
- Fix: suggestion
- Scope: module

Reported

import { Iterator } from "destack:iter";

declare function record(value: &readonly int32): void;

function observe(values: Iterator<int32>): Iterator<int32> {
    return values.map((value) => {
        record(value);
        value
    });
}
Accepted

import { Iterator } from "destack:iter";

declare function record(value: &readonly int32): void;

function observe(values: Iterator<int32>): Iterator<int32> {
    return values.inspect((value) => {
        record(value);
    });
}
Prior art

- Clippy · manualinspect

language/linter/src/rules/style/manualiteratorinspect.rs:8