I'm using https://github.com/open-xml-templating/docxtemplater

My data:

var person = {
  name: 'Joe',
  address: {
    city: 'Stockholm',
    postal: 45123
  }
}

How do write the syntax in the docx with this nested object?

This is not working:

{address.city}

Can't find any example in the docs.

There are three possibilities, one with angular-expressions, one by writing a very simple parser yourself, or one without any parser.

With angular expressions

The "angular-expressions" parser gives you the ability to parse more complex expressions :

{address.city}

To use it you also have to install angular-expressions :

npm install --save angular-expressions

const expressionParser = require("docxtemplater/expressions.js");
const doc = new Docxtemplater(zip, { parser: expressionParser });
doc.render(/* data */);

Without angular expressions :

const doc = new Docxtemplater(zip, {
    paragraphLoop: true,
    linebreaks: true,
    parser(tag) {
        const splitted = tag.split(".");
        return {
            get(scope) {
                if (tag === ".") {
                    return scope;
                }
                let s = scope;
                for (
                    let i = 0, len = splitted.length;
                    i < len;
                    i++
                ) {
                    const key = splitted[i];
                    s = s[key];
                }
                return s;
            },
        };
    },
});
doc.render({
    user: {
        name: "John",
    },
});

This allows you to parse {user.name} with nested property access.

Using just builtin features :

If you don't want to add a parser option (which relies on an external dependency), you will have to write in your template :

{#address}{city}{/}

This creates a section that will have as current context the "address" object, and then fetch the "city" key from the address object.