static decimalPlaces(str) {
        const [, decimalPart] = str.split('.');
        if (!this.isUndefined(decimalPart)) {
            return decimalPart.length;
        }

        return 0;
    }
Return the number of decimal places if the parameter is a string that represents a float number, and that number has a decimal part.

@param {string} str
@returns {int}