Nuxt/packages/nuxt/src/core/modules.ts

import { normalizeModuleTranspilePath, useNuxt } from '@nuxt/kit'

interface AddModuleTranspilesOptions {
  additionalModules?: string[]
}

export const addModuleTranspiles = (opts: AddModuleTranspilesOptions = {}) => {
  const nuxt = useNuxt()

  const modules = [
    ...opts.additionalModules || [],
    ...nuxt.options.modules,
    ...nuxt.options._modules
  ]
    .map(m => typeof m === 'string' ? m : Array.isArray(m) ? m[0] : m.src)
    .filter(m => typeof m === 'string')
    .map(normalizeModuleTranspilePath)

  // Try to sanitize modules to better match imports
  nuxt.options.build.transpile =
    nuxt.options.build.transpile.map(m => typeof m === 'string' ? m.split('node_modules/').pop() : m)
      .filter(<T>(x: T | undefined): x is T => !!x)

  function isTranspilePresent (mod: string) {
    return nuxt.options.build.transpile.some(t => !(t instanceof Function) && (t instanceof RegExp ? t.test(mod) : new RegExp(t).test(mod)))
  }

  // Automatically add used modules to the transpile
  for (const module of modules) {
    if (!isTranspilePresent(module)) {
      nuxt.options.build.transpile.push(module)
    }
  }
}