Merge nested if conditions

[chrisfalaska]

Merge nested if conditions (merge-nested-ifs)

i18n.js

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  if (window.MutationObserver) {
    const observer = new MutationObserver(handleChange);
    observer.observe(document.documentElement, { attributes: true,
      attributeFilter: ['lang'] });
  }
}

if (typeof window !== "undefined" && window.MutationObserver) {
      const observer = new MutationObserver(handleChange);
      observer.observe(document.documentElement, { attributes: true,
        attributeFilter: ['lang'] });
}

Explanation

Reading deeply nested conditional code is confusing, since you have to keep track of which
conditions relate to which levels. We therefore strive to reduce nesting where
possible, and the situation where two if conditions can be combined using
and is an easy win.

Originally posted by @sourcery-ai[bot] in AlaskaAirlines/auro-formkit#16 (comment)