index.js

'use strict'

const pathToRegExp = require('path-to-regexp')
const typeis = require('type-is').is

function setNoCacheHeaders(ctx) {
  ctx.set('Cache-Control', 'no-store, no-cache, must-revalidate')
  ctx.set('Pragma', 'no-cache')
  ctx.set('Expires', 0)
}

module.exports = function noCache(options) {
  options = options || {}
  options.global = Boolean(options.global)

  const paths = options.paths || []
  const types = options.types || []
  const config = options.config || {
    sensitive: true,
    strict: true
  }

  const pathsFinal = paths.map(path => pathToRegExp(path, [], config))

  if (options.global) {
    return async function noCacheForAll(ctx, next) {
      await next()
      setNoCacheHeaders(ctx)
    }
  }

  // only load modules if needed
  return async function noCache(ctx, next) {
    await next()
    if (typeis(ctx.type, types) || pathsFinal.some(pathFinal => pathFinal.exec(ctx.path))) {
      setNoCacheHeaders(ctx)
    }
  }
}