prefer-is-nil.md

Prefer R.isNil

When checking that a value is undefined or null (but not false or ''), it is more concise to use R.isNil instead.

Rule Details

This rule takes no arguments.

The following patterns are considered warnings:

var t = !R.isNull(x) && !R.isUndefined(x);

var t = x === undefined || x === null;

The following patterns are not considered warnings:

var t = R.isNil(x);

var t = R.isUndefined(x) || R.isNull(y);

When Not To Use It

If you do not want to enforce using R.isNil, and prefer using specific checks instead.