Replacing placeholders in Email Template

Question

What is the better way to replace placeholders in email module?

So, I have made a mail service which takes parameters like templatename , receiverMail & locals. locals have the values for placeholders.

var locals = {
    username: "John",
    website: "w3schools.com",
    url: "http:// abc. com"
};

mail.sendMail('Registration', 'xyz.com', locals);

Relevant Code from Mail service :-

var mailOptions = {
        from: "Abc <[email protected]>", // sender address
        to: email, // list of receivers
        subject: template_subject, // Subject line
        html: template_html // html body

template_html contents the html body including the placeholders this is pulled from mongodb.

The locals are dynamic & can be increased or decreased.

What is the way to replace the placeholders?

Template:- (pls note these placeholders are dynamic & can be changed by admin)

<p>
    Hi {{username}},
</p>
<p>
   Xyz would like you to join it's network on <a href="{{url}}">xyz</a>.
    <br />
    Our website {{ website }}
</p>

Answer 1

We can use regular expressions to search and replace the template with the user specified data.

I have put up a small demo at

Working DEMO

Here I am replacing the template with the actual data.

I am using the below code for replacing the data in the template:

for (var i = 0; i < data.length; i++) {
        var obj = data[i];
        output +="<p>" + template.replace(/\<%=(.*?)\%>/g, function(match, property) {
            return obj[property];
        }) + "</p>";

 }

Answer 2

In this function replace all the tags with the values from the object passed in the parameter using RegExp

In this example use {{key}} in my html template

function replaceTemplateValues(template, values){
    let html = template;
    for (let key in values) {
        html = html.replace(new RegExp('{{' + key + '}}', 'g'), values[key]);
    }
    return html;
}