ov-segment

src/ov-segment.js

Attributes

attribute
`deadband`
`digits`	read-only as a property: pass it as an attribute, never as a prop
`frozen-after`
`max`
`max-age`
`min`
`places`
`segments`
`source`
`substituted`
`unit`
`value`	also a property

Properties

A reading property takes a reading directly, which an attribute cannot: an attribute is a string, and a reading may be an array, a dropout, or a value carrying an age.

property	type	kind	accepts	staleness
`value`	`Reading`	reading	a single reading	marks it stale

WHAT A READING PROPERTY ACCEPTS

set to	what happens
`null`	set deliberately to nothing. A dropout, renders a refusal
`number`	drawn
`undefined`	property never set; falls through to source, then attribute
`{value, age}`	drawn, and marked stale when age exceeds max-age

A reading property never coerces null to 0 and never drops it from an array. Strings are passed through unnormalised, so "01.50" stays "01.50".

READ-ONLY PROPERTIES

digits, glyphs, mode

The names in bold are also attributes. Assigning one as a prop throws, so set them in markup.

Events

None.

Using it

import 'overscan'
import 'overscan/overscan.css'

<ov-segment
  value="318.4"
  digits="5"
  unit="K"
  style="--ov-seg-width:14px"
></ov-segment>

import { OvSegment } from 'overscan/react'

<OvSegment
  digits="5"
  unit="K"
  value={reading}
/>

import { OvSegment } from 'overscan/vue'

<OvSegment
  digits="5"
  unit="K"
  :value="reading"
/>

import OvSegment from 'overscan/svelte/OvSegment.svelte'

<OvSegment
  digits="5"
  unit="K"
  value={reading}
/>

The CSS is a separate import in every framework. A single element can be imported on its own instead of the whole kit: import 'overscan/src/ov-chart.js'

A reading is set as a PROPERTY, never an attribute. An attribute is a string, so an array cannot survive one and a null arrives as the word "null", which the protocol would read as a value rather than a dropout.

Every ov: event is bound with addEventListener. The colon has no declarative spelling in Svelte 5, where the on: directive is gone and "onov:commit" is not an identifier, nor in JSX. Vue can bind it.

The wrapper applies attributes ITSELF and hands the framework nothing but a ref. All three frameworks set a prop as a property when the name exists on the element, and this kit has 77 getter-only properties across 43 elements. Assigning one throws, and in React it does not degrade: the whole tree fails to render. 13 elements have a getter-only name that is also a real attribute (at, bearing, digits, duration, floor, fov, fresh, hold, lat, lon, period, pitch, range, ring, rings, span, step, sweep, sweeps, traces, value), which are the ones a reader would naturally pass in markup.