element-props

Normalize access to element attributes/properties.

import elementProps from 'element-props.js'

let el = document.getElementById('my-element')
props = elementProps(el, { z: Number })

// numeric
props.x = 1
el.getAttribute('x') // '1'
props.x // 1

// boolean
el.setAttribute('disabled', '')
props.disabled // true
props.disabled = false
el.getAttribute('disabled') // 'false'
props.disabled = null
el.getAttribute('disabled') // null

// functions
props.onclick = e => ()

// spread
{...props} // { y: false, x: 1, id: 'my-element' }

API

props = elementProps(element, types?, onchange?)

Create props for an element, with optional types = { propName: Type } (compat. with attr-types). Type is any data class like Number, Boolean, String, Array, Object, Data, RegExp, or string => data function like JSON.parse (used for Array and Object).

import elementProps from 'element-props';

let props = elementProps(el, {n:Number, b:Boolean, o:Object, a:Array, s:String, d:Date}, (key, val) => {})
props.n = '1'
el.setAttribute('b', '')
el.s = 'abc'
el.setAttribute('a', '1,2,3')
el.setAttribute('o', '{foo:"bar"}')

{...props} // {n: 1, b: true, s: 'abc', o: {foo:'bar'}, a: [1,2,3]}

props handle input elements - text, checkbox, select:

let el = document.querySelector('#checkbox')
let props = elementProps(el)
props.value = true

el.value // 'on'
el.checked // true
props.value // true
el.getAttribute('value') // 'on'
el.getAttribute('checked') // ''

prop(el, key, value)

Set key prop/attribute value depending on value type.

• on* property can only be a function.
• onEvt === onevt.
• style can only be an object or a string.
• class can be a string, object or a string.
• id can only be a string.
• Empty strings are considered booleans: <a disabled /> → a.props.disabled === true

CamelCase key name is mapped to dash-case for attribute.

[get, set] = input(el)

Create getter/setter for an input depending on element type.

value = parse(string, Type?)

Convert string value into defined type or detect type automatically (tiny auto-parse).

import { parse } from './element-props.js'

parse('true', Boolean) // true
parse('123') // 123
parse('1,2,3', Array) // [1, 2, 3]
parse('{ a: 1, b: 2 }', Object) // { a: 1, b: 2}

polyfill

Add props to all HTML elements by including augment for Element.prototype.props:

import 'element-props/augment.js'

document.body.id = 'my-body'
document.body.props // { id: 'my-body' }

Design

Internally uses Proxy, (no IE11 support, but in theory possible with MutationObserver fallback)

Inspired by this tweet with spreading hint.

See also

• Element properties proposal
• templize
• attr-types

License

ISC © Dmitry Iv.