mochajs/mocha · error · Error

ERR_MOCHA_FORBIDDEN_EXCLUSIVITY

ERR_MOCHA_FORBIDDEN_EXCLUSIVITY

Error message

`.only` forbidden by --forbid-only (or "`.only` is not supported in parallel mode" in workers)

What it means

Error "`.only` forbidden by --forbid-only (or "`.only` is not supported in parallel mode" in workers)" thrown in mochajs/mocha.

Source

Thrown at lib/interfaces/common.js:98

     *
     * @param {string} name
     * @param {Function} fn
     */
    afterEach: function (name, fn) {
      return suites[0].afterEach(name, fn);
    },

    suite: {
      /**
       * Create an exclusive Suite; convenience function
       * See docstring for create() below.
       *
       * @param {Object} opts
       * @returns {Suite}
       */
      only: function only(opts) {
        if (mocha.options.forbidOnly) {
          throw createForbiddenExclusivityError(mocha);
        }
        opts.isOnly = true;
        return this.create(opts);
      },

      /**
       * Create a Suite, but skip it; convenience function
       * See docstring for create() below.
       *
       * @param {Object} opts
       * @returns {Suite}
       */
      skip: function skip(opts) {
        opts.pending = true;
        return this.create(opts);
      },

      /**

View on GitHub (pinned to 6bcbee4fd9)

When it happens

Trigger: Thrown at lib/interfaces/common.js:98 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Authentication and authorization failures — expired tokens, bad credentials, and missing scopes.

AI-assisted analysis of mochajs/mocha@6bcbee4fd9 (2026-09-01). Data as JSON: /api/errors/7dbdb129393e265f. Report an issue: GitHub.