Things you can use when you drop support for IE8

Here is a list of things you can start using if you drop support for IE8.

JavaScript

Object

• Object.create
• Object.defineProperties
• Object.getPrototypeOf
• Object.keys
• Object.seal
• Object.freeze
• Object.preventExtensions
• Object.isSealed
• Object.isFrozen
• Object.isExtensible
• Object.getOwnPropertyNames

Array

• Array.isArray
• Array.prototype.indexOf
• Array.prototype.lastIndexOf
• Array.prototype.every
• Array.prototype.some
• Array.prototype.forEach
• Array.prototype.map
• Array.prototype.filter
• Array.prototype.reduce
• Array.prototype.reduceRight

Date

• Date.prototype.toISOString
• Date.now

Function

• Function.prototype.bind

String

• String.prototype.trim

Getters and Setters

• Getter in property initializer
• Setter in property initializer

Other

• Property access on strings
• Reserved words as property names
• Zero-width chars in identifiers
• parseInt() ignores leading zeros
• Immutable undefined

HTML & CSS

• ::selection CSS pseudo-element
• CSS font-stretch
• CSS currentColor value
• CSS3 2D Transforms
• CSS background-position edge offsets
• CSS3 Multiple backgrounds
• CSS3 Background-image options
• CSS3 Box-shadow
• CSS3 Colors
• CSS3 Media Queries
• CSS3 Border-radius (rounded corners)
• getComputedStyle
• SVG in CSS backgrounds
• Text API for Canvas
• Canvas (basic support)
• DOMContentLoaded
• getElementsByClassName
• Document Object Model Range
• Navigation Timing API
• New semantic elements
• Audio element
• Video element
• Inline SVG in HTML5
• Geolocation
• MPEG-4/H.264 video format
• MP3 audio format
• WOFF – Web Open Font Format
• XHTML served as application/xhtml+xml
• SVG fragment identifiers
• SVG (basic support)
• SVG in HTML img element
• calc() as CSS unit value

Thanks

Huge shout out to @kangax‘s compatibility table and @Fyrd‘s Can I use for making this ridiculously easy to figure out.