docx-js/src/file/paragraph/run/sequential-identifier-instruction.ts

// http://officeopenxml.com/WPfieldInstructions.php
import { SpaceType } from "file/space-type";
import { XmlComponent } from "file/xml-components";

import { TextAttributes } from "./text-attributes";

export class SequentialIdentifierInstruction extends XmlComponent {
    constructor(identifier: string) {
        super("w:instrText");
        this.root.push(new TextAttributes({ space: SpaceType.PRESERVE }));
        this.root.push(`SEQ ${identifier}`);
    }
}