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[proximity] does it have a proximity sensor?

From: Marcos Caceres <w3c@marcosc.com>
Date: Sun, 20 May 2012 13:15:08 +0100
Message-ID: <4FB8E04C.3060604@marcosc.com>
To: "public-device-apis@w3.org" <public-device-apis@w3.org>
I'm still a bit concerned that the API lacks a way to check if a device 
has a proximity sensor. Current generation of tablets do not contain 
proximity sensors because there is no use case for putting a tablet next 
to your head, and because of the way they are held: a user's hands would 
constantly be activating the sensor when switching to landscape/portrait 
because of the form factor. This means that a developer could save 
themselves a bunch of trouble (and potentially some memory) but not 
setting up event listeners and other code for devices that don't contain 
a proximity sensor. I also don't know of any tablets that intend to put 
alternative proximity sensors on devices (e.g., behind the screen) or 
that those proximity sensors won't have a clear use case that would 
warrant their own API (e.g., a stylus API).

I see two potential ways of checking for this (assuming we go with my 
previously proposed API changes)...

PROPOSAL 1. Making near attribute "near" attribute nullable

Example:
//check if we have a proximity sensor
if(navigator.proximity.near !== null) {
     //we are good to go...
}

Pros:
  * Piggy-backs on already required attribute;

Cons:
  * Slightly changes the semantics "near" (gives it two data types, 
which can kinda suck sometimes)

PROPOSAL 2. add a new attribute

Example:
//check if we have a proximity sensor
if(navigator.proximity.<hasSensor>) {
     //we are good to go...
}

Pros:
   * leaves "near" attribute alone.
   * has its own clean semantics.

Cons:
   * adds another attribute

Kind regards,
Marcos

-- 
Marcos Caceres
http://datadriven.com.au
Received on Sunday, 20 May 2012 12:15:40 GMT

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