prefer-slice-pattern

Prefer slice patterns over indexing after a length guard

A length guard followed by fixed indexing separates a sequence's required shape from its extracted values.
Instead, you SHOULD use a slice pattern to check and bind the elements together.

- Category: style
- Level: warning
- Fix: none
- Scope: module

Reported

function firstPair(values: int32[]): int32 | undefined {
    if (values.length >= 2) {
        return values[0] + values[1];
    }

    return undefined;
}
Accepted

function firstPair(values: int32[]): int32 | undefined {
    if (const [first, second, ...] = values) {
        return first + second;
    }

    return undefined;
}
Prior art

- Clippy · indexrefutableslice

language/linter/src/rules/style/preferslicepattern.rs:9