docx-js/src/file/media/media.ts

import * as sizeOf from "image-size";

import { File } from "../file";
import { ImageParagraph } from "../paragraph";
import { IMediaData } from "./data";
import { Image } from "./image";

interface IHackedFile {
    currentRelationshipId: number;
}

export class Media {
    public static addImage(file: File, buffer: Buffer, width?: number, height?: number): Image {
        // Workaround to expose id without exposing to API
        const exposedFile = (file as {}) as IHackedFile;
        const mediaData = file.Media.addMedia(buffer, exposedFile.currentRelationshipId++, width, height);
        file.DocumentRelationships.createRelationship(
            mediaData.referenceId,
            "http://schemas.openxmlformats.org/officeDocument/2006/relationships/image",
            `media/${mediaData.fileName}`,
        );

        return new Image(new ImageParagraph(mediaData));
    }

    private static generateId(): string {
        // https://gist.github.com/6174/6062387
        return (
            Math.random()
                .toString(36)
                .substring(2, 15) +
            Math.random()
                .toString(36)
                .substring(2, 15)
        );
    }

    private readonly map: Map<string, IMediaData>;

    constructor() {
        this.map = new Map<string, IMediaData>();
    }

    public getMedia(key: string): IMediaData {
        const data = this.map.get(key);

        if (data === undefined) {
            throw new Error(`Cannot find image with the key ${key}`);
        }

        return data;
    }

    public addMedia(buffer: Buffer, referenceId: number, width?: number, height?: number): IMediaData {
        const key = `${Media.generateId()}.png`;
        let dimensions;
        if (width && height) {
            dimensions = {
                width: width,
                height: height,
            };
        } else {
            dimensions = sizeOf(buffer);
        }

        return this.createMedia(key, referenceId, dimensions, buffer);
    }

    private createMedia(
        key: string,
        relationshipsCount: number,
        dimensions: { width: number; height: number },
        data: Buffer,
        filePath?: string,
    ): IMediaData {
        const imageData = {
            referenceId: this.map.size + relationshipsCount + 1,
            stream: data,
            path: filePath,
            fileName: key,
            dimensions: {
                pixels: {
                    x: dimensions.width,
                    y: dimensions.height,
                },
                emus: {
                    x: dimensions.width * 9525,
                    y: dimensions.height * 9525,
                },
            },
        };

        this.map.set(key, imageData);

        return imageData;
    }

    public get Array(): IMediaData[] {
        const array = new Array<IMediaData>();

        this.map.forEach((data) => {
            array.push(data);
        });

        return array;
    }
}