QJSEngine template engine

main.cpp

#include <QJSEngine>
#include <QDebug>
#include <QCoreApplication>
#include <QFile>
#include <QTextStream>
#include <QVariantMap>

QString loadFile(QString fileName)
{
	QFile file(fileName);

	if (!file.open(QIODevice::ReadOnly)) {
		qDebug() << "Unable to open file " << fileName;
		return QString("");
	}

	QTextStream fstream(&file);

	QString data = fstream.readAll();

	file.close();

	return data;
}

int main(int argc, char *argv[])
{
	QCoreApplication app(argc, argv);

	QJSEngine js;

	auto data = loadFile("ejs.min.js");

	QJSValue result = js.evaluate(data, "ejs.min.js");
	if (result.isError()) {
		qDebug() << "result: " << result.property("lineNumber").toInt() << ":" << result.toString();
	}

	auto tmpl = loadFile("main.ejs");
	js.globalObject().setProperty("template", tmpl);

	QString jsRender("ejs.render(template, data);");

	QVariantMap renderData;
	QStringList users;
	users << "jerry" << "steven" << "maurice";
	renderData.insert("users", users);

	js.globalObject().setProperty("data", js.toScriptValue(renderData));

	result = js.evaluate(jsRender, "render.js");
	if (result.isError()) {
		qDebug() << "result: " << result.property("lineNumber").toInt() << ":" << result.toString();
	} else {
		QTextStream ts( stdout );
		ts << result.toString();
	}

	return 0;
}

main.ejs

<% if (users) { %>
There are <%- users.length %> users:
<% users.forEach(function(user) { -%>
- <%= user %>
<% }); %>
JSON: <%- JSON.stringify(users) -%>

<% if (users.includes("jerry")) { -%>
There is a user named jerry!
<% } -%>

<% users.forEach(function(user) { -%>
<%_ switch (user) {
case 'steven' : -%>
There is a user named steven!
	<% break;
} -%>
<% }); -%>

<% } -%>

main.pro

SOURCES = main.cpp
QT += core qml

QJSEngine templating example

Download ejs.min.js from https://cdn.jsdelivr.net/npm/ejs@3.1.6/ejs.min.js
See also https://cpp.hotexamples.com/examples/-/QJSEngine/toScriptValue/cpp-qjsengine-toscriptvalue-method-examples.html