docx-js/ts/docx/document/body/index.ts

import { Attributes, XmlComponent } from "../../xml-components";
import { SectionProperties } from "./section-properties";

export class Body extends XmlComponent {

    constructor() {
        super("w:body");
        // this.root.push(new SectionProperties()); not actually needed
    }

    public push(component: XmlComponent): void {
        // this.root.splice(this.body.length - 1, 0, component);
        this.root.push(component);
    }
}