3dealer/resources/js/stimulus/quantity-controller.js

import { Controller } from '@hotwired/stimulus'

export default class extends Controller {
    static targets = ['input', 'decrement']
    static values  = { min: { type: Number, default: 1 } }

    connect() {
        this.#updateDecrement()
    }

    increment() {
        this.#setValue(this.#current + 1)
    }

    decrement() {
        this.#setValue(this.#current - 1)
    }

    clamp() {
        this.#setValue(this.#current)
    }

    get #current() {
        return parseInt(this.inputTarget.value, 10) || this.minValue
    }

    #setValue(val) {
        const clamped = Math.max(this.minValue, val)
        this.inputTarget.value = clamped
        this.#updateDecrement()
        this.inputTarget.dispatchEvent(new Event('quantity:change', { bubbles: true }))
    }

    #updateDecrement() {
        const atMin = this.#current <= this.minValue
        this.decrementTarget.disabled = atMin
        this.decrementTarget.setAttribute('aria-disabled', atMin)
    }
}