getWhitespaceMinWidth() {
        this._checkPendingChanges();
        if (this._minWidth === -1) {
            let minWidth = 0;
            for (let i = 0, len = this._arr.length; i < len; i++) {
                minWidth = Math.max(minWidth, this._arr[i].minWidth);
            }
            this._minWidth = minWidth;
        }
        return this._minWidth;
    }
The maximum min width for all whitespaces.