Is there a way to add modifiers to an existing provider?

[remihuigen]

I'm hosting media on Cloudinary and using it together with Nuxt Image. To handle both images and videos, I currently define two providers:

// nuxt.config.ts
/**
 * Nuxt Image module configuration
 * @link https://image.nuxt.com/get-started/installation
 */
image: {
  provider: 'cloudinary',
  cloudinary: {
    baseURL: `https://res.cloudinary.com/${process.env.CLD_CLOUD}/image/upload/`,
    modifiers: {
      quality: 'auto:best',
      format: 'auto',
    },
  },
  providers: {
    video: {
      provider: 'cloudinary',
      options: {
        baseURL: `https://res.cloudinary.com/${process.env.CLD_CLOUD}/video/upload/`,
      },
    },
  },
}

Defining the extra video provider lets me use <NuxtImg> for video thumbnails, which works fine functionally. The issue is that video transformations use a different set of modifiers than images. Previously, this wasn’t a problem because modifiers weren’t typed. After the latest Nuxt Image release, passing video-specific modifiers now leads to type errors:

<NuxtImg 
  :src="poster"
  provider="video"
  :width="width"
  :height="height"
  fit="fill"
  :alt="data.title"
  :loading="lazy ? 'lazy' : 'eager'"
  :modifiers="{
    aspectRatio: ASPECT_RATIO,
    // @ts-expect-error video-specific modifier
    so: '5'
  }"
  class="w-full h-full object-cover object-center"
/>

Is there a way to extend the provider definition so video transforms—like startOffset—are recognized as valid modifiers? I could implement a custom provider, but that feels like overkill for what I’m trying to solve.

[mosioc]

Hey @remihuigen

Few months late but dug into the source and the Cloudinary docs to figure out exactly what's happening. Looking at the Cloudinary provider source, the modifier pipeline works like this:

1. CloudinaryModifiers is the type interface; so and duration aren't in it, hence your TS error.
2. operationsGenerator has a keyMap that converts modifier names to Cloudinary URL params; so isn't in there either, so even if you bypass the types, it never reaches the generated URL.

So you need to solve both: make TypeScript accept the modifiers and make them actually reach the URL.

Option 1: Module augmentation + keyMap extension; Extend the types so TS is happy:

// types/nuxt-image-cloudinary.d.ts
import type { CloudinaryModifiers } from '@nuxt/image'

declare module '@nuxt/image' {
  interface CloudinaryModifiers {
    so?: string | number
    duration?: string | number
  }
}

But this alone won't make them work. The keyMap still doesn't know about them. For that, you'd need to either fork the Cloudinary provider and add so: 'so' and duration: 'du' to the keyMap, or use a custom provider (Option 3 below).

Option 2: Typed wrapper. If you just want the TS error gone:

// utils/video-modifiers.ts
interface VideoModifiers {
  width?: number
  height?: number
  fit?: string
  so?: string | number
  duration?: string | number
  aspectRatio?: string
}

export const videoMods = (overrides: VideoModifiers = {}) => ({
  aspectRatio: '16:9',
  so: '5',
  ...overrides,
})

<NuxtImg provider="video" :modifiers="videoMods({ so: '5' })" />

TypeScript won't complain. But check if so actually appears in the generated URL. If it doesn't, you need Option 3.

Option 3: Custom provider. Looking at the Cloudinary Transformation Reference, the actual URL params are so (start offset), eo (end offset), and du (duration). There is no startOffset parameter in Cloudinary's API. A video variant of the provider handles both types and URL generation:

// providers/video-cloudinary.ts
import { joinURL, encodePath } from 'ufo'
import { defu } from 'defu'
import type { ImageModifiers } from '@nuxt/image'
import { createOperationsGenerator } from '@nuxt/image/runtime/utils'
import { defineProvider } from '@nuxt/image/runtime/utils/provider'

export interface VideoCloudinaryModifiers extends ImageModifiers {
  width: number
  height: number
  fit: string
  format: string
  quality: string
  aspectRatio: string
  so: string | number
  duration: string | number
}

const operationsGenerator = createOperationsGenerator({
  keyMap: {
    width: 'w',
    height: 'h',
    fit: 'c',
    format: 'f',
    quality: 'q',
    aspectRatio: 'ar',
    so: 'so',
    duration: 'du',
  },
  joinWith: ',',
  formatter: (key, value) => encodePath(key.includes('_') ? `${key}:${value}` : `${key}_${value}`),
})

const defaultModifiers = {
  format: 'auto',
  quality: 'auto',
}

export default defineProvider({
  getImage: (src, { modifiers, baseURL = '/' }) => {
    const merged = defu(modifiers, defaultModifiers)
    const operations = operationsGenerator(merged as any)
    return {
      url: joinURL(baseURL, operations, src),
    }
  },
})

// nuxt.config.ts
image: {
  providers: {
    video: {
      provider: '~/providers/video-cloudinary',
      options: {
        baseURL: `https://res.cloudinary.com/${process.env.CLD_CLOUD}/video/upload/`,
      },
    },
  },
}

Now so and duration are fully typed and they appear in the generated URL as so_5 and du_10. The keyMap tells the generator how to convert each modifier name to Cloudinary's URL param format.