accounts-frontend/packages/app/services/loader.ts

// On page initialization loader is already visible, so initial value is 1
let stack = 1;

export function show(): void {
    if (++stack >= 0) {
        const loader = document.getElementById('loader');

        if (!loader) {
            throw new Error('Can not find loader element');
        }

        loader.classList.add('is-active');
    }
}

export function hide(): void {
    if (--stack <= 0) {
        stack = 0;
        const loader = document.getElementById('loader');

        if (!loader) {
            throw new Error('Can not find loader element');
        }

        loader.classList.remove('is-active', 'is-first-launch');
    }
}