highlight_current() {
        const res = this.get_closest_date();
        if (!res) return;

        const [_, el] = res;
        el.classList.add('current-date-highlight');

        const diff_in_units = date_utils.diff(
            new Date(),
            this.gantt_start,
            this.config.unit,
        );

        const left =
            (diff_in_units / this.config.step) * this.config.column_width;

        this.$current_highlight = this.create_el({
            top: this.config.header_height,
            left,
            height: this.grid_height - this.config.header_height,
            classes: 'current-highlight',
            append_to: this.$container,
        });
        this.$current_ball_highlight = this.create_el({
            top: this.config.header_height - 6,
            left: left - 2.5,
            width: 6,
            height: 6,
            classes: 'current-ball-highlight',
            append_to: this.$header,
        });
    }
Compute the horizontal x-axis distance and associated date for the current date and view.

@returns Object containing the x-axis distance and date of the current date, or null if the current date is out of the gantt range.