redraw()

Description

Updates the DOM after a change in the application data layer.

You DON'T need to call it if data is modified within the execution context of an event handler defined in a Mithril.js view, or after request completion when using m.request. The autoredraw system, which is built on top of m.redraw() will take care of it.

You DO need to call it in setTimeout/setInterval/requestAnimationFrame callbacks, or callbacks from 3rd party libraries.

Signature

m.redraw()

Argument	Type	Required	Description
returns			Returns nothing

Static members

m.redraw.sync

m.redraw.sync()

Argument	Type	Required	Description
returns			Returns nothing

How it works

When callbacks outside of Mithril.js run, you need to notify Mithril.js' rendering engine that a redraw is needed. External callbacks could be setTimeout/setInterval/requestAnimationFrame callbacks, web socket library callbacks, event handlers in jQuery plugins, third party XHR request callbacks, etc.

To trigger a redraw, call m.redraw(). Note that m.redraw only works if you used m.mount or m.route. If you rendered via m.render, you should use m.render to redraw.

m.redraw() always triggers an asynchronous redraws, whereas m.redraw.sync() triggers a synchronous one. m.redraw() is tied to window.requestAnimationFrame(). It will thus typically fire at most 60 times per second. It may fire faster if your monitor has a higher refresh rate.

m.redraw.sync() is mostly intended to make videos play work in iOS. That only works in response to user-triggered events. It comes with several caveat:

• You should not call m.redraw.sync() from a lifecycle method or the view() method of a component. Doing so will result in undefined behavior (it throws an error when possible).
• m.redraw.sync() called from an event handler can cause the DOM to be modified while an event is bubbling. Depending on the structure of the old and new DOM trees, the event can finish the bubbling phase in the new tree and trigger unwanted handlers.
• It is not throttled. One call to m.redraw.sync() causes immediately one m.render() call per root registered with m.mount() or m.route().

m.redraw() doesn't have any of those issues, you can call it from wherever you like.