Semantic-Org/Semantic-UI · warning

Caching responses locally requires session storage

Error message

Caching responses locally requires session storage

What it means

This error is logged by the API module's read.cachedResponse() (api.js:144-146) and write.cachedResponse() (api.js:160-162) functions when settings.cache is set to 'local' (requesting sessionStorage-based caching) but window.Storage is undefined. window.Storage is the browser's built-in interface for sessionStorage and localStorage; if it is unavailable, the module cannot cache or retrieve responses locally.

Source

Thrown at src/definitions/behaviors/api.js:1137

  // request aborted
  onAbort     : function(errorMessage, $module) {},

  successTest : false,

  // errors
  error : {
    beforeSend        : 'The before send function has aborted the request',
    error             : 'There was an error with your request',
    exitConditions    : 'API Request Aborted. Exit conditions met',
    JSONParse         : 'JSON could not be parsed during error handling',
    legacyParameters  : 'You are using legacy API success callback names',
    method            : 'The method you called is not defined',
    missingAction     : 'API action used but no url was defined',
    missingSerialize  : 'jquery-serialize-object is required to add form data to an existing data object',
    missingURL        : 'No URL specified for api event',
    noReturnedValue   : 'The beforeSend callback must return a settings object, beforeSend ignored.',
    noStorage         : 'Caching responses locally requires session storage',
    parseError        : 'There was an error parsing your request',
    requiredParameter : 'Missing a required URL parameter: ',
    statusMessage     : 'Server gave an error: ',
    timeout           : 'Your request timed out'
  },

  regExp  : {
    required : /\{\$*[A-z0-9]+\}/g,
    optional : /\{\/\$*[A-z0-9]+\}/g,
  },

  className: {
    loading : 'loading',
    error   : 'error'
  },

  selector: {
    disabled : '.disabled',

View on GitHub (pinned to 597843ab84)

Solutions

1. Use a different cache strategy: set settings.cache to false or 'browser' (relies on HTTP cache headers instead of sessionStorage).
2. Wrap sessionStorage usage in a feature detection check before enabling cache: 'local'.
3. Implement a fallback cache mechanism (e.g., in-memory Map) when sessionStorage is unavailable.

Example fix

// before
$('.el').api({
  url: '/api/data',
  cache: 'local'
  // fails in private browsing or sandboxed iframes
});

// after
var canCache = (function() {
  try { return window.Storage !== undefined; } catch(e) { return false; }
})();
$('.el').api({
  url: '/api/data',
  cache: canCache ? 'local' : false
});

// Feature-detect sessionStorage before enabling local cache
var storageAvailable = (function() {
  try {
    var t = '__test__';
    sessionStorage.setItem(t, t);
    sessionStorage.removeItem(t);
    return true;
  } catch(e) { return false; }
})();
$('.el').api({
  cache: storageAvailable ? 'local' : false,
  url: '/api/data'
});

// Check if sessionStorage is accessible
function isSessionStorageAvailable() {
  try { return window.Storage !== undefined && !!window.sessionStorage; }
  catch(e) { return false; }
}

When it happens

Trigger: Configuring $('.el').api({ cache: 'local' }) in an environment where sessionStorage is not available. This occurs in private/incognito browsing modes in some older browsers, in Safari when cookies/storage are blocked, in embedded contexts (iframes with sandbox restrictions), or in server-side rendering environments where window and sessionStorage do not exist.

Common situations: Older browsers (IE7 and below) that lack sessionStorage. Safari with cross-site tracking prevention blocking storage in iframes. Headless browser testing environments (some configurations). Content Security Policy or sandbox attributes restricting storage access. Private browsing modes in mobile browsers.

Related errors

• The before send function has aborted the request
• There was an error with your request
• API Request Aborted. Exit conditions met
• JSON could not be parsed during error handling
• You are using legacy API success callback names

AI-assisted analysis of Semantic-Org/Semantic-UI@597843ab84 (2026-08-13). Data as JSON: /api/errors/46634896ae1a183c. Report an issue: GitHub.