March 2026
Determine the Type of a Variable in JavaScript
Some stuff to look at:
- Number.isFinite(checkVar)
- Number.isInteger(checkVar)
- Number.isNaN(checkVar)
- typeof checkVar === "number"
- checkVar instanceof DocumentFragment === true
- checkVar instanceof Element === true
- checkVar instanceof Node === true
- checkVar instanceof Array === true
- Array.isArray(checkVar)
- typeof checkVar === 'object' && checkVar !== null && !Array.isArray(checkVar)
- checkValue === null
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