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/**
* @license
* Copyright 2018 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
const assert = require('assert')
const path = require('path')
const { URL } = require('url')
function determineAsValue ({ optionsAs, href }) {
assert(href, `The 'href' parameter was not provided.`)
switch (typeof optionsAs) {
case 'string': {
return optionsAs
}
case 'function': {
return optionsAs(href)
}
case 'undefined': {
// If `as` value is not provided in option, dynamically determine the correct
// value based on the suffix of filename.
// We only care about the pathname, so just use any domain when constructing the URL.
const url = new URL(href, 'https://example.com')
const extension = path.extname(url.pathname)
if (extension === '.css') {
return 'style'
}
if (extension === '.woff2') {
return 'font'
}
return 'script'
}
default:
throw new Error(`The 'as' option isn't set to a recognized value: ${optionsAs}`)
}
}
module.exports = determineAsValue