modrinth/apps/frontend/src/composables/fetch.js

export const useBaseFetch = async (url, options = {}, skipAuth = false) => {
	const config = useRuntimeConfig()
	let base = import.meta.server ? config.apiBaseUrl : config.public.apiBaseUrl

	if (!options.headers) {
		options.headers = {}
	}

	if (import.meta.server) {
		options.headers['x-ratelimit-key'] = config.rateLimitKey
	}

	if (!skipAuth) {
		const auth = await useAuth()

		options.headers.Authorization = auth.value.token
	}

	if (options.apiVersion || options.internal) {
		// Base may end in /vD/ or /vD. We would need to replace the digit with the new version number
		// and keep the trailing slash if it exists
		const baseVersion = base.match(/\/v\d\//)

		const replaceStr = options.internal ? `/_internal/` : `/v${options.apiVersion}/`

		if (baseVersion) {
			base = base.replace(baseVersion[0], replaceStr)
		} else {
			base = base.replace(/\/v\d$/, replaceStr)
		}

		delete options.apiVersion
	}

	return await $fetch(`${base}${url}`, options)
}