NaturalIntelligence/fast-xml-parser

const EOL = "\n";

/**
 * 
 * @param {array} jArray 
 * @param {any} options 
 * @returns 
 */
function toXml(jArray, options) {
    let indentation = "";
    if (options.format && options.indentBy.length > 0) {
        indentation = EOL;
    }
    return arrToStr(jArray, options, "", indentation);
}

function arrToStr(arr, options, jPath, indentation) {
    let xmlStr = "";
    let isPreviousElementTag = false;

    for (let i = 0; i < arr.length; i++) {
        const tagObj = arr[i];
        const tagName = propName(tagObj);
        if(tagName === undefined) continue;

        let newJPath = "";
        if (jPath.length === 0) newJPath = tagName
        else newJPath = `${jPath}.${tagName}`;

        if (tagName === options.textNodeName) {
            let tagText = tagObj[tagName];
            if (!isStopNode(newJPath, options)) {
                tagText = options.tagValueProcessor(tagName, tagText);
                tagText = replaceEntitiesValue(tagText, options);
            }
            if (isPreviousElementTag) {
                xmlStr += indentation;
            }
            xmlStr += tagText;
            isPreviousElementTag = false;
            continue;
        } else if (tagName === options.cdataPropName) {
            if (isPreviousElementTag) {
                xmlStr += indentation;
            }
            xmlStr += `<![CDATA[${tagObj[tagName][0][options.textNodeName]}]]>`;
            isPreviousElementTag = false;
            continue;
        } else if (tagName === options.commentPropName) {
            xmlStr += indentation + `<!--${tagObj[tagName][0][options.textNodeName]}-->`;
            isPreviousElementTag = true;
            continue;
        } else if (tagName[0] === "?") {
            const attStr = attr_to_str(tagObj[":@"], options);
            const tempInd = tagName === "?xml" ? "" : indentation;
            let piTextNodeName = tagObj[tagName][0][options.textNodeName];
            piTextNodeName = piTextNodeName.length !== 0 ? " " + piTextNodeName : ""; //remove extra spacing
            xmlStr += tempInd + `<${tagName}${piTextNodeName}${attStr}?>`;
            isPreviousElementTag = true;
            continue;
        }
        let newIdentation = indentation;
        if (newIdentation !== "") {
            newIdentation += options.indentBy;
        }
        const attStr = attr_to_str(tagObj[":@"], options);
        const tagStart = indentation + `<${tagName}${attStr}`;
        const tagValue = arrToStr(tagObj[tagName], options, newJPath, newIdentation);
        if (options.unpairedTags.indexOf(tagName) !== -1) {
            if (options.suppressUnpairedNode) xmlStr += tagStart + ">";
            else xmlStr += tagStart + "/>";
        } else if ((!tagValue || tagValue.length === 0) && options.suppressEmptyNode) {
            xmlStr += tagStart + "/>";
        } else if (tagValue && tagValue.endsWith(">")) {
            xmlStr += tagStart + `>${tagValue}${indentation}</${tagName}>`;
        } else {
            xmlStr += tagStart + ">";
            if (tagValue && indentation !== "" && (tagValue.includes("/>") || tagValue.includes("</"))) {
                xmlStr += indentation + options.indentBy + tagValue + indentation;
            } else {
                xmlStr += tagValue;
            }
            xmlStr += `</${tagName}>`;
        }
        isPreviousElementTag = true;
    }

    return xmlStr;
}

function propName(obj) {
    const keys = Object.keys(obj);
    for (let i = 0; i < keys.length; i++) {
        const key = keys[i];
        if(!obj.hasOwnProperty(key)) continue;
        if (key !== ":@") return key;
    }
}

function attr_to_str(attrMap, options) {
    let attrStr = "";
    if (attrMap && !options.ignoreAttributes) {
        for (let attr in attrMap) {
            if(!attrMap.hasOwnProperty(attr)) continue;
            let attrVal = options.attributeValueProcessor(attr, attrMap[attr]);
            attrVal = replaceEntitiesValue(attrVal, options);
            if (attrVal === true && options.suppressBooleanAttributes) {
                attrStr += ` ${attr.substr(options.attributeNamePrefix.length)}`;
            } else {
                attrStr += ` ${attr.substr(options.attributeNamePrefix.length)}="${attrVal}"`;
            }
        }
    }
    return attrStr;
}

function isStopNode(jPath, options) {
    jPath = jPath.substr(0, jPath.length - options.textNodeName.length - 1);
    let tagName = jPath.substr(jPath.lastIndexOf(".") + 1);
    for (let index in options.stopNodes) {
        if (options.stopNodes[index] === jPath || options.stopNodes[index] === "*." + tagName) return true;
    }
    return false;
}

function replaceEntitiesValue(textValue, options) {
    if (textValue && textValue.length > 0 && options.processEntities) {
        for (let i = 0; i < options.entities.length; i++) {
            const entity = options.entities[i];
            textValue = textValue.replace(entity.regex, entity.val);
        }
    }
    return textValue;
}
module.exports = toXml;