March 2019 web platform update

Now widely available on the web platform
Widely available

Array copyWithin(): The copyWithin() method of arrays and typed arrays shifts or copies items of an array to another index of the array without changing its length. Learn more.
Array.from(): The Array.from() and typed array .from() static methods copy items from an iterable or array-like object to make a new array. Learn more.
Array includes(): The includes() method of arrays and typed arrays returns whether a given value appears in the array. Learn more.
Array iterators: Arrays are iterable with the for…of statement and enumerable with the methods entries(), keys(), and values(). Learn more.
Array.of(): The Array.of() and typed array .of() static methods create new arrays from the values of any number of arguments. Learn more.
@font-face: The @font-face CSS at-rule creates a custom font-family value. The at-rule's descriptors set the font's name, source, and various display settings. Learn more.
Typed array iterators: Typed arrays are iterable with the for…of statement and enumerable with the methods entries(), keys(), and values(). Learn more.

Abortable fetch: If you construct a fetch request with an AbortSignal, you can cancel the request. Learn more.
AbortController and AbortSignal: The AbortController and AbortSignal APIs allow you to cancel an ongoing operation, such as a fetch() request. Learn more.
Intersection observer: The Intersection Observer API asynchronously observes changes in the intersection of a target element with an ancestor element or with a top-level document's viewport. Learn more.

Constructed stylesheets: The CSSStyleSheet constructor creates a new stylesheet which can be shared between a document and multiple shadow roots using adoptedStyleSheets. Learn more.
Media session: The navigator.mediaSession API integrates with platform UI for media playback. It can be used to set metadata such as title and artwork, and to handle user actions like playing, pausing, or seeking. Learn more.
Preloading responsive images: The imagesrcset and imagesizes attributes with the rel="preload" attribute for the <link> HTML element starts fetching responsive images before they're found in the body of the document. Learn more.

Constructed stylesheets: The CSSStyleSheet constructor creates a new stylesheet which can be shared between a document and multiple shadow roots using adoptedStyleSheets. Learn more.
Preloading responsive images: The imagesrcset and imagesizes attributes with the rel="preload" attribute for the <link> HTML element starts fetching responsive images before they're found in the body of the document. Learn more.

Grid animation: Grid animation allows you to animate the grid-template-columns and grid-template-rows CSS properties. Learn more.

Grid animation: Grid animation allows you to animate the grid-template-columns and grid-template-rows CSS properties. Learn more.

ARIA attribute reflection: WAI-ARIA attributes have corresponding properties on Element and ElementInternals objects. Learn more.
Conic gradients: The conic-gradient() and repeating-conic-gradient() CSS functions create backgrounds that progress between two or more colors around a center point. Learn more.
<datalist>: The <datalist> element defines a set of recommended values for an <input> element. Browsers may show a dropdown menu of all options, or matching options as the user types. Learn more.
Grid: CSS Grid is a two-dimensional layout system, which lays content out in rows and columns. Learn more.
prefers-color-scheme: The prefers-color-scheme CSS media query detects the requested color scheme, light or dark. Learn more.

ARIA attribute reflection: WAI-ARIA attributes have corresponding properties on Element and ElementInternals objects. Learn more.
Conic gradients: The conic-gradient() and repeating-conic-gradient() CSS functions create backgrounds that progress between two or more colors around a center point. Learn more.
<datalist>: The <datalist> element defines a set of recommended values for an <input> element. Browsers may show a dropdown menu of all options, or matching options as the user types. Learn more.
Grid: CSS Grid is a two-dimensional layout system, which lays content out in rows and columns. Learn more.