e5d578a849
Disable the confirmation dialog when deleting files in the VS Code explorer to streamline the development workflow and reduce friction during file management operations.
138 lines
2.6 KiB
JavaScript
138 lines
2.6 KiB
JavaScript
/*!
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* fresh
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* Copyright(c) 2012 TJ Holowaychuk
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* Copyright(c) 2016-2017 Douglas Christopher Wilson
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* MIT Licensed
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*/
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'use strict'
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/**
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* RegExp to check for no-cache token in Cache-Control.
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* @private
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*/
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var CACHE_CONTROL_NO_CACHE_REGEXP = /(?:^|,)\s*?no-cache\s*?(?:,|$)/
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/**
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* Module exports.
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* @public
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*/
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module.exports = fresh
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/**
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* Check freshness of the response using request and response headers.
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*
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* @param {Object} reqHeaders
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* @param {Object} resHeaders
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* @return {Boolean}
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* @public
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*/
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function fresh (reqHeaders, resHeaders) {
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// fields
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var modifiedSince = reqHeaders['if-modified-since']
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var noneMatch = reqHeaders['if-none-match']
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// unconditional request
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if (!modifiedSince && !noneMatch) {
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return false
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}
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// Always return stale when Cache-Control: no-cache
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// to support end-to-end reload requests
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// https://tools.ietf.org/html/rfc2616#section-14.9.4
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var cacheControl = reqHeaders['cache-control']
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if (cacheControl && CACHE_CONTROL_NO_CACHE_REGEXP.test(cacheControl)) {
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return false
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}
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// if-none-match
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if (noneMatch && noneMatch !== '*') {
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var etag = resHeaders['etag']
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if (!etag) {
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return false
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}
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var etagStale = true
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var matches = parseTokenList(noneMatch)
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for (var i = 0; i < matches.length; i++) {
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var match = matches[i]
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if (match === etag || match === 'W/' + etag || 'W/' + match === etag) {
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etagStale = false
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break
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}
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}
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if (etagStale) {
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return false
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}
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}
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// if-modified-since
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if (modifiedSince) {
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var lastModified = resHeaders['last-modified']
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var modifiedStale = !lastModified || !(parseHttpDate(lastModified) <= parseHttpDate(modifiedSince))
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if (modifiedStale) {
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return false
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}
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}
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return true
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}
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/**
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* Parse an HTTP Date into a number.
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*
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* @param {string} date
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* @private
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*/
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function parseHttpDate (date) {
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var timestamp = date && Date.parse(date)
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// istanbul ignore next: guard against date.js Date.parse patching
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return typeof timestamp === 'number'
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? timestamp
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: NaN
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}
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/**
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* Parse a HTTP token list.
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*
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* @param {string} str
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* @private
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*/
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function parseTokenList (str) {
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var end = 0
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var list = []
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var start = 0
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// gather tokens
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for (var i = 0, len = str.length; i < len; i++) {
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switch (str.charCodeAt(i)) {
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case 0x20: /* */
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if (start === end) {
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start = end = i + 1
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}
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break
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case 0x2c: /* , */
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list.push(str.substring(start, end))
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start = end = i + 1
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break
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default:
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end = i + 1
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break
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}
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}
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// final token
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list.push(str.substring(start, end))
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return list
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}
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