formData in web-components

Hello, I made a web component:

class Toggle extends HTMLElement {
    #toggle = /*html*/`
    <input type="checkbox" ${this.checked ? 'checked' : ''} />
    `

    constructor() {
        super()

        const shadow = this.attachShadow({mode: 'open'})
        shadow.innerHTML = this.#toggle
        this.internals = this.attachInternals()

        shadow.querySelector('input').addEventListener('input', ({currentTarget}) => {
            this.checked = currentTarget.checked
        })
    }

    static formAssociated = true;

    get checked() {
        return this.hasAttribute('checked');
    }

    set checked(isChecked) {
        this.internals.setFormValue(this.getAttribute('value'))
        isChecked ? this.setAttribute('checked', '') : this.removeAttribute('checked')
    }
}
customElements.define('my-toggle', GfToggle)

class Toggle extends HTMLElement {
    #toggle = /*html*/`
    <input type="checkbox" ${this.checked ? 'checked' : ''} />
    `

    constructor() {
        super()

        const shadow = this.attachShadow({mode: 'open'})
        shadow.innerHTML = this.#toggle
        this.internals = this.attachInternals()

        shadow.querySelector('input').addEventListener('input', ({currentTarget}) => {
            this.checked = currentTarget.checked
        })
    }

    static formAssociated = true;

    get checked() {
        return this.hasAttribute('checked');
    }

    set checked(isChecked) {
        this.internals.setFormValue(this.getAttribute('value'))
        isChecked ? this.setAttribute('checked', '') : this.removeAttribute('checked')
    }
}
customElements.define('my-toggle', GfToggle)

This is the html:

<form>
  <my-toggle name="bla" value="foo"></my-toggle>
</form>

<form>
  <my-toggle name="bla" value="foo"></my-toggle>
</form>

And it works, the form element recognizes my-toggle as a member of the form. But console.log(new FormData(form)) gives me an empty FormData object. Why?

17 Replies

ἔρως•14mo ago

instead of adding html, try creating the element using document.createElement but honestly, if you want to make a toggle, i would just do a label with styles

Wonderbear•14mo ago

I need more than one element to make a toggle, thats why I wanted to use a custom element

ἔρως•14mo ago

or you can just set the appearence: none on the checkbox, and now you can style with a ::before and ::after

Wonderbear•14mo ago

Why?

ἔρως•14mo ago

and its all 1 element because adding html like that may have unintended side effects does it have? i dont know

Wonderbear•14mo ago

I use innerHTML because I want to be able to write readable html instead of calling dozens of methods But I'll try using :before and :after and get rid of the component

get out...!•14mo ago

it will be more convient and this type of work

ἔρως•14mo ago

trust me, it is a lot easier you can set the checkbox to have appearance: none with a height, width, border-radius and background the ::before can have a height that's 100% height - 2x the width of the border and have 50% border radius and then you can just transition the background and position of the ::before

get out...!•14mo ago

here is the code <!DOCTYPE html> <html> <style> .myinput { appearance: none; display: inline-block; position: relative; width: 20px; height: 20px; border: 2px solid gray; border-radius: 4px; transition: background-color, border-color ease-in 0.2s; cursor: pointer; } .myinput::before { content: ''; display: none; position: absolute; top: 1px; left: 50%; translate: -50% 0; height: 60%; width: 6px; border-right: 2px solid white; border-bottom: 2px solid white; transform: rotate(45deg); transition: display ease-in 0.2s; } .myinput:hover { border-color: lightGray; } .myinput:checked { background: green; } .myinput:checked::before { display: inline-block;
} </style> <body> <form> <input class="myinput" type="checkbox"/> </form> </body> </html> you can do more using html data attribute

ἔρως•14mo ago

display doesnt transition: it jumps from "none" to "block"

Wonderbear•14mo ago

yup I already almost have it

ἔρως•14mo ago

and this way, you dont have to try to shoehorn your custom element into the formdata

Wonderbear•14mo ago

Thanks, using a web-component was, as so often, the wrong way

get out...!•14mo ago

my bad, Instead I use opacity

Wonderbear•14mo ago

What do you need opacity for anyway?

label.toggle {
    display: flex;
}
input[type="checkbox"].toggle {
    appearance: none;
    height: .8rem;
    width: 2rem;
    background-color: var(--gray);
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-radius: 99px;
    position: relative;
    margin: .3rem 0;
    margin-right: .3rem;
    transition: .25s;
}
input[type="checkbox"].toggle:focus {
    border: none;
}
input[type="checkbox"].toggle::after {
    content: "";
    position: absolute;
    display: block;
    height: 1rem;
    width: 1rem;
    border-radius: 99px;
    background-color: var(--darkgray);
    box-shadow: var(--shadow-sm);
    transition: .25s;
    box-sizing: border-box;
}
input[type="checkbox"].toggle:checked::after {
    transform: translateX(100%);
    background-color: #000;
}

label.toggle {
    display: flex;
}
input[type="checkbox"].toggle {
    appearance: none;
    height: .8rem;
    width: 2rem;
    background-color: var(--gray);
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-radius: 99px;
    position: relative;
    margin: .3rem 0;
    margin-right: .3rem;
    transition: .25s;
}
input[type="checkbox"].toggle:focus {
    border: none;
}
input[type="checkbox"].toggle::after {
    content: "";
    position: absolute;
    display: block;
    height: 1rem;
    width: 1rem;
    border-radius: 99px;
    background-color: var(--darkgray);
    box-shadow: var(--shadow-sm);
    transition: .25s;
    box-sizing: border-box;
}
input[type="checkbox"].toggle:checked::after {
    transform: translateX(100%);
    background-color: #000;
}

ἔρως•14mo ago

transitioning from hidden to visible also, avoid using transition without properties that means that everything will transition, when the css loads including width, height and other properties that cause layout shifting

get out...!•14mo ago

good advise

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formData in web-components