_getSignPosition() {
        let result;
        if (this.settings.currencySymbol) {
            const currencySymbolLen = this.settings.currencySymbol.length;
            const value = AutoNumericHelper.getElementValue(this.domElement);
            if (this.settings.currencySymbolPlacement === AutoNumeric.options.currencySymbolPlacement.prefix) {
                const hasNeg = this.settings.negativeSignCharacter && value && value.charAt(0) === this.settings.negativeSignCharacter;
                if (hasNeg) {
                    result = [1, currencySymbolLen + 1];
                } else {
                    result = [0, currencySymbolLen];
                }
            } else {
                const valueLen = value.length;
                result = [valueLen - currencySymbolLen, valueLen];
            }
        } else {
            result = [1000, -1];
        }

        return result;
    }
Helper function for `_expandSelectionOnSign()`.

@returns {Array} Array containing [signPosition, currencySymbolPosition] of a formatted value
@private