Quick Feature Detection in JavaScript

If you want to create an object that you can use to query features you can do so like this :-

const featureDetection = {
    hasFill: 'fill' in Array,
    hasFrom: 'from' in Array
}

console.log(featureDetection.hasFill) // true if Array has fill (ES2015)
console.log(featureDetection.hasFrom) // true if Array has from (ES2015)

if(!featureDetection.hasFill)
{
    // handle the case where we can't use fill (i.e. polyfill)
}

if(!featureDetection.hasFrom)
{
    // handle the case where we can't use from (i.e. polyfill)
}

in returns true if the specified property is on the specified object (or it's prototype chain)

Of course, there are more standard ways of doing this like Modernizr or @babel/preset-env if you are feeling particulary fancy but I thought this was neat little use case when you don't want to bring in a heavy dependency.

benlowery.co.uk

Quick Feature Detection in JavaScript