Changelog
11.7.4 (2025-10-01)
🩹 Fixes
📚 Documentation
- migrate remaining legacy wiki pages to main documentation (#5465) (bff9166)
🧹 Chores
11.7.3 (2025-09-30)
🩹 Fixes
- use original require() error for TS files if ERR_UNKNOWN_FILE_EXTENSION (#5408) (ebdbc48)
📚 Documentation
🤖 Automation
- deps: bump actions/setup-node in the github-actions group (#5459) (48c6f40)
11.7.2 (2025-09-01)
🩹 Fixes
- fail with an informative error message on a file with a broken default import (#5413) (b0e6135)
- load mjs files correctly (#5429) (a947b9b)
📚 Documentation
🧹 Chores
🤖 Automation
- deps: bump actions/checkout in the github-actions group (#5419) (03ac2d0)
11.7.1 (2025-06-24)
🩹 Fixes
- always fallback to import() if require() fails (#5384) (295c168)
🧹 Chores
11.7.0 (2025-06-18)
🌟 Features
11.6.0 (2025-06-09)
🌟 Features
11.5.0 (2025-05-22)
🌟 Features
11.4.0 (2025-05-19)
🌟 Features
📚 Documentation
- added CHANGELOG.md note around 11.1 yargs-parser update (#5362) (618415d)
11.3.0 (2025-05-16)
🌟 Features
- add option to use posix exit code upon fatal signal (#4989) (91bbf85)
📚 Documentation
🧹 Chores
- remove prerelease setting in release-please config (#5363) (8878f22)
11.2.2 (2025-04-10)
🩹 Fixes
📚 Documentation
11.2.1 (2025-04-10)
🩹 Fixes
📚 Documentation
- fix new website typos, improve readability (#5312) (fbceb19)
🧹 Chores
11.2.0 (2025-03-17)
🌟 Features
- enable reporters to show relative paths of tests (#5292) (81ea666)
📚 Documentation
🧹 Chores
11.1.0 (2025-01-02)
🌟 Features
- bump yargs to 17 (#5165) (8f1c8d8)
- Note that this also included a version bump of yargs-parserfrom^20.2.9to^21.1., which fixed a bug that caused extra quotes in file paths to be removed.
See #5341 for more information.
 
- replace strip-ansiwithutil.stripVTControlCharacters(#5267) (3c191c0), closes #5265
11.0.2 (2024-12-09)
🩹 Fixes
- catch exceptions setting Error.stackTraceLimit (#5254) (259f8f8)
- error handling for unexpected numeric arguments passed to cli (#5263) (210d658)
📚 Documentation
- correct outdated status: accepting prslink (#5268) (f729cd0)
- replace "New in" with "Since" in version annotations (#5262) (6f10d12)
11.0.1 (2024-12-02)
🌟 Features
📚 Documentation
- fix examples for linkPartialObjectsmethods (#5255) (34e0e52)
11.0.0 (2024-11-11)
⚠ BREAKING CHANGES
- adapt new engine range for Mocha 11 (#5216)
🌟 Features
🩹 Fixes
📚 Documentation
10.8.2 (2024-10-30)
🩹 Fixes
- support errors with circular dependencies in object values with --parallel (#5212) (ba0fefe)
- test link in html reporter (#5224) (f054acc)
📚 Documentation
- indicate 'exports' interface does not work in browsers (#5181) (14e640e)
🧹 Chores
- fix docs builds by re-adding eleventy and ignoring gitignore again (#5240) (881e3b0)
🤖 Automation
- deps: bump the github-actions group with 1 update (#5132) (e536ab2)
10.8.1 (2024-10-29)
🩹 Fixes
10.8.0 (2024-10-29)
🌟 Features
🩹 Fixes
📚 Documentation
🧹 Chores
- fix npm scripts on windows (#5219) (1173da0)
- remove trailing whitespace in SECURITY.md (7563e59)
10.7.3 (2024-08-09)
🩹 Fixes
10.7.2 (2024-08-06)
📚 Documentation
🧹 Chores
10.7.1 (2024-08-06)
🩹 Fixes
- crash with --parallel and --retries both enabled (#5173) (d7013dd)
🧹 Chores
10.7.0 / 2024-07-20
:tada: Enhancements
10.6.1 / 2024-07-20
:bug: Fixes
10.6.0 / 2024-07-02
:tada: Enhancements
10.5.2 / 2024-06-25
:bug: Fixes
- #5032 fix: better tracking of seen objects in error serialization (@sam-super)
10.5.1 / 2024-06-24
:bug: Fixes
- #5086 fix: Add error handling for nonexistent file case with --file option (@khoaHyh)
10.5.0 / 2024-06-24
:tada: Enhancements
- #5015 feat: use \<progress> and \<svg> for browser progress indicator instead of \<canvas> (@yourWaifu)
- #5143 feat: allow using any 3.x chokidar dependencies (@simhnna)
- #4835 feat: add MOCHA_OPTIONS env variable (@icholy)
:bug: Fixes
:nut_and_bolt: Other
10.4.0 / 2024-03-26
:tada: Enhancements
:bug: Fixes
- #5074 fix: harden error handling in lib/cli/run.js(@stalet)
:nut_and_bolt: Other
10.3.0 / 2024-02-08
This is a stable release equivalent to 10.30.0-prerelease.
10.3.0-prerelease / 2024-01-18
This is a prerelease version to test our ability to release.
Other than removing or updating dependencies, it contains no intended user-facing changes.
:nut_and_bolt: Other
10.2.0 / 2022-12-11
:tada: Enhancements
- #4945: API: add possibility to decorate ESM name before import (@j0tunn)
:bug: Fixes
:book: Documentation
10.1.0 / 2022-10-16
:tada: Enhancements
- #4896: Browser: add support for prefers-color-scheme: dark(@greggman)
:nut_and_bolt: Other
10.0.0 / 2022-05-01
:boom: Breaking Changes
:nut_and_bolt: Other
Also thanks to @ea2305 and @SukkaW for improvements to our documentation.
9.2.2 / 2022-03-11
:bug: Fixes
:nut_and_bolt: Other
9.2.1 / 2022-02-19
:bug: Fixes
9.2.0 / 2022-01-24
:tada: Enhancements
- #4813: Parallel: assign each worker a worker-id (@forty)
:nut_and_bolt: Other
9.1.4 / 2022-01-14
:bug: Fixes
:nut_and_bolt: Other
9.1.3 / 2021-10-15
:bug: Fixes
:nut_and_bolt: Other
9.1.2 / 2021-09-25
:bug: Fixes
:nut_and_bolt: Other
9.1.1 / 2021-08-28
:bug: Fixes
9.1.0 / 2021-08-20
:tada: Enhancements
9.0.3 / 2021-07-25
:bug: Fixes
9.0.2 / 2021-07-03
:bug: Fixes
- #4668: ESM: make --require <dir>work with newimport-first loading (@giltayar)
:nut_and_bolt: Other
9.0.1 / 2021-06-18
:nut_and_bolt: Other
- #4657: Browser: add separate bundle for modern browsers (@juergba)
We added a separate browser bundle mocha-es2018.js in javascript ES2018, as we skipped the transpilation down to ES5. This is an experimental step towards freezing Mocha's support of IE11.
9.0.0 / 2021-06-07
:boom: Breaking Changes
Mocha is going ESM-first! This means that it will now use ESM import(test_file) to load the test files, instead of the CommonJS require(test_file). This is not a problem, as import can also load most files that require does. In the rare cases where this fails, it will fallback to require(...). This ESM-first approach is the next step in Mocha's ESM migration, and allows ESM loaders to load and transform the test file.
- #4636: Remove deprecated - utils.lookupFiles()(@juergba)
 
- #4638: Limit the size of - actual/- expectedfor- diffgeneration (@juergba)
 
- #4389: Refactoring: Consuming log-symbols alternate to code for win32 in reporters/base (@MoonSupport) 
:tada: Enhancements
:bug: Fixes
:nut_and_bolt: Other
8.4.0 / 2021-05-07
:tada: Enhancements
:bug: Fixes
:book: Documentation
- #4630: Add options.requireto Mocha constructor forroot hookplugins on parallel runs (@juergba)
- #4617: Dynamically generating tests with top-level awaitand ESM test files (@juergba)
- #4608: Update default file extensions (@outsideris)
Also thanks to @outsideris for various improvements on our GH actions workflows.
8.3.2 / 2021-03-12
:bug: Fixes
:book: Documentation
8.3.1 / 2021-03-06
:bug: Fixes
- #4577: Browser: fix EvalErrorcaused by regenerator-runtime (@snoack)
- #4574: ESM: allow importfrom mocha in parallel mode (@nicojs)
8.3.0 / 2021-02-11
:tada: Enhancements
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
Also thanks to @outsideris and @HyunSangHan for various fixes to our website and documentation.
8.2.1 / 2020-11-02
Fixed stuff.
:bug: Fixes
- #4489: Fix problematic handling of otherwise-unhandled Promiserejections and erroneous "done()called twice" errors (@boneskull)
- #4496: Avoid MaxListenersExceededWarningin watch mode (@boneskull)
Also thanks to @akeating for a documentation fix!
8.2.0 / 2020-10-16
The major feature added in v8.2.0 is addition of support for global fixtures.
While Mocha has always had the ability to run setup and teardown via a hook (e.g., a before() at the top level of a test file) when running tests in serial, Mocha v8.0.0 added support for parallel runs. Parallel runs are incompatible with this strategy; e.g., a top-level before() would only run for the file in which it was defined.
With global fixtures, Mocha can now perform user-defined setup and teardown regardless of mode, and these fixtures are guaranteed to run once and only once. This holds for parallel mode, serial mode, and even "watch" mode (the teardown will run once you hit Ctrl-C, just before Mocha finally exits). Tasks such as starting and stopping servers are well-suited to global fixtures, but not sharing resources--global fixtures do not share context with your test files (but they do share context with each other).
Here's a short example of usage:
exports.mochaGlobalSetup = async function () {
  this.server = await startSomeServer({port: process.env.TEST_PORT});
  console.log(`server running on port ${this.server.port}`);
};
exports.mochaGlobalTeardown = async function () {
  
  await this.server.stop();
  console.log(`server on port ${this.server.port} stopped`);
};
Fixtures are loaded with --require, e.g., mocha --require fixtures.js.
For detailed information, please see the documentation and this handy-dandy flowchart to help understand the differences between hooks, root hook plugins, and global fixtures (and when you should use each).
:tada: Enhancements
For implementors of custom reporters:
- #4409: Parallel mode and custom reporter improvements (@boneskull):
- Support custom worker-process-only reporters (Runner.prototype.workerReporter()); reporters should subclassParallelBufferedReporterinmocha/lib/nodejs/reporters/parallel-buffered
- Allow opt-in of object reference matching for "sufficiently advanced" custom reporters (Runner.prototype.linkPartialObjects()); use if strict object equality is needed when consumingRunnerevent data
- Enable detection of parallel mode (Runner.prototype.isParallelMode())
 
:bug: Fixes
- #4476: Workaround for profoundly bizarre issue affecting npmv6.x causing some of Mocha's deps to be installed whenmochais present in a package'sdevDependenciesandnpm install --productionis run the package's working copy (@boneskull)
- #4465: Worker processes guaranteed (as opposed to "very likely") to exit before Mocha does; fixes a problem when using nycwith Mocha in parallel mode (@boneskull)
- #4419: Restore lookupFiles()inmocha/lib/utils, which was broken/missing in Mocha v8.1.0; it now prints a deprecation warning (useconst {lookupFiles} = require('mocha/lib/cli')instead) (@boneskull)
Thanks to @AviVahl, @donghoon-song, @ValeriaVG, @znarf, @sujin-park, and @majecty for other helpful contributions!
8.1.3 / 2020-08-28
:bug: Fixes
- #4425: Restore Mocha.utils.lookupFiles()and Webpack compatibility (both broken since v8.1.0);Mocha.utils.lookupFiles()is now deprecated and will be removed in the next major revision of Mocha; userequire('mocha/lib/cli').lookupFilesinstead (@boneskull)
8.1.2 / 2020-08-25
:bug: Fixes
:lock: Security Fixes
:book: Documentation
8.1.1 / 2020-08-04
:bug: Fixes
- #4394: Fix regression wherein certain reporters did not correctly detect terminal width (@boneskull)
8.1.0 / 2020-07-30
In this release, Mocha now builds its browser bundle with Rollup and Babel, which will provide the project's codebase more flexibility and consistency.
While we've been diligent about backwards compatibility, it's possible consumers of the browser bundle will encounter differences (other than an increase in the bundle size). If you do encounter an issue with the build, please report it here.
This release does not drop support for IE11.
Other community contributions came from @Devjeel, @Harsha509 and @sharath2106. Thank you to everyone who contributed to this release!
Do you read Korean? See this guide to running parallel tests in Mocha, translated by our maintainer, @outsideris.
:tada: Enhancements
:bug: Fixes
:lock: Security Fixes
:book: Documentation & Website
:nut_and_bolt: Other
- #4293: Use Rollup and Babel in build pipeline; add source map to published files (@Munter)
8.0.1 / 2020-06-10
The obligatory patch after a major.
:bug: Fixes
8.0.0 / 2020-06-10
In this major release, Mocha adds the ability to run tests in parallel. Better late than never! Please note the breaking changes detailed below.
Let's welcome @giltayar and @nicojs to the maintenance team!
:boom: Breaking Changes
- #4164: Mocha v8.0.0 now requires Node.js v10.12.0 or newer. Mocha no longer supports the Node.js v8.x line ("Carbon"), which entered End-of-Life at the end of 2019 (@UlisesGascon) 
- #4175: Having been deprecated with a warning since v7.0.0, - mocha.optsis no longer supported (@juergba)
 - :sparkles: WORKAROUND: Replace - mocha.optswith a configuration file.
 
- #4260: Remove - enableTimeout()(- this.enableTimeout()) from the context object (@craigtaub)
 - :sparkles: WORKAROUND: Replace usage of - this.enableTimeout(false)in your tests with- this.timeout(0).
 
- #4315: The - specoption no longer supports a comma-delimited list of files (@juergba)
 - :sparkles: WORKAROUND: Use an array instead (e.g., - "spec": "foo.js,bar.js"becomes- "spec": ["foo.js", "bar.js"]).
 
- #4309: Drop support for Node.js v13.x line, which is now End-of-Life (@juergba) 
- #4282: - --forbid-onlywill throw an error even if exclusive tests are avoided via- --grepor other means (@arvidOtt)
 
- #4223: The context object's - skip()(- this.skip()) in a "before all" (- before()) hook will no longer execute subsequent sibling hooks, in addition to hooks in child suites (@juergba)
 
- #4178: Remove previously soft-deprecated APIs (@wnghdcjfe): - 
- Mocha.prototype.ignoreLeaks()
- Mocha.prototype.useColors()
- Mocha.prototype.useInlineDiffs()
- Mocha.prototype.hideDiff()
 
:tada: Enhancements
:book: Documentation
- #4246: Add documentation for parallel mode and Root Hook plugins (@boneskull)
:nut_and_bolt: Other
:bug: Fixes
(All bug fixes in Mocha v8.0.0 are also breaking changes, and are listed above)
7.2.0 / 2020-05-22
:tada: Enhancements
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
7.1.2 / 2020-04-26
:nut_and_bolt: Other
:book: Documentation
7.1.1 / 2020-03-18
:lock: Security Fixes
- #4204: Update dependencies mkdirp, yargs-parser and yargs (@juergba)
:bug: Fixes
:book: Documentation
7.1.0 / 2020-02-26
:tada: Enhancements
#4038: Add Node.js native ESM support (@giltayar)
Mocha supports writing your test files as ES modules:
- Node.js only v12.11.0 and above
- Node.js below v13.2.0, you must set --experimental-modulesoption
- current limitations: please check our documentation
- for programmatic usage: see API: loadFilesAsync()
Note: Node.JS native ECMAScript Modules implementation has status: Stability: 1 - Experimental
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
7.0.1 / 2020-01-25
:bug: Fixes
- #4165: Fix exception when skipping tests programmatically (@juergba)
- #4153: Restore backwards compatibility for reporterOptions(@holm)
- #4150: Fix recovery of an open test upon uncaught exception (@juergba)
- #4147: Fix regression of leaking uncaught exception handler (@juergba)
:book: Documentation
:nut_and_bolt: Other
7.0.0 / 2020-01-05
:boom: Breaking Changes
- #3885: Drop Node.js v6.x support (@mojosoeun)
- #3890: Remove Node.js debug-related flags --debug/--debug-brkand deprecatedebugargument (@juergba)
- #3962: Changes to command-line options (@ParkSB):
- --list-interfacesreplaces- --interfaces
- --list-reportersreplaces- --reporters
 
- Hook pattern of this.skip()(@juergba):
- #3859: When conditionally skipping in a ittest, relatedafterEachhooks are now executed
- #3741: When conditionally skipping in a beforeEachhook, subsequent innerbeforeEachhooks are now skipped and relatedafterEachhooks are executed
- #4136: Disallow this.skip()withinafterhooks
 
- #3967: Remove deprecated getOptions()andlib/cli/options.js(@juergba)
- #4083: Uncaught exception in pendingtest: don't swallow, but retrospectively fail the test for correct exit code (@juergba)
- #4004: Align Mochaconstructor's option names with command-line options (@juergba)
:tada: Enhancements
- #3980: Refactor and improve --watchmode with chokidar (@geigerzaehler):
- adds command-line options --watch-filesand--watch-ignore
- removes --watch-extensions
 
- #3979: Type "rs\n" to restart tests (@broofa)
:fax: Deprecations
These are soft-deprecated, and will emit a warning upon use. Support will be removed in (likely) the next major version of Mocha:
:bug: Fixes
:mag: Coverage
:book: Documentation
:nut_and_bolt: Other
6.2.3 / 2020-03-25
:lock: Security Fixes
6.2.2 / 2019-10-18
:bug: Fixes
:book: Documentation
6.2.1 / 2019-09-29
:bug: Fixes
- #3955: tty.getWindowSize is not a function inside a "worker_threads" worker (@1999)
- #3970: remove extraGlobals() (@juergba)
- #3984: Update yargs-unparser to v1.6.0 (@juergba)
- #3983: Package 'esm': spawn child-process for correct loading (@juergba)
- #3986: Update yargs to v13.3.0 and yargs-parser to v13.1.1 (@juergba)
:book: Documentation
6.2.0 / 2019-07-18
:tada: Enhancements
:bug: Fixes
:book: Documentation
:mag: Coverage
:nut_and_bolt: Other
6.1.4 / 2019-04-18
:lock: Security Fixes
6.1.3 / 2019-04-11
:bug: Fixes
6.1.2 / 2019-04-08
:bug: Fixes
- #3867: Re-publish v6.1.1 from POSIX OS to avoid dropped executable flags (@boneskull)
6.1.1 / 2019-04-07
:bug: Fixes
6.1.0 / 2019-04-07
:lock: Security Fixes
- #3845: Update dependency "js-yaml" to v3.13.0 per npm security advisory (@plroebuck)
:tada: Enhancements
- #3766: Make reporter constructor support optional optionsparameter (@plroebuck)
- #3760: Add support for config files with .jsoncextension (@sstephant)
:fax: Deprecations
These are soft-deprecated, and will emit a warning upon use. Support will be removed in (likely) the next major version of Mocha:
:bug: Fixes
- #3829: Use cwd-relative pathname to load config file (@plroebuck)
- #3745: Fix async calls of this.skip()in "before each" hooks (@juergba)
- #3669: Enable --allow-uncaughtfor uncaught exceptions thrown inside hooks (@givanse)
and some regressions:
:book: Documentation
:nut_and_bolt: Other
- #3830: Replace dependency "findup-sync" with "find-up" for faster startup (@cspotcode)
- #3799: Update devDependencies to fix many npm vulnerabilities (@XhmikosR)
6.0.2 / 2019-02-25
:bug: Fixes
Two more regressions fixed:
- #3768: Test file paths no longer dropped from mocha.opts(@boneskull)
- #3767: --requiredoes not break on module names that look like certainnodeflags (@boneskull)
6.0.1 / 2019-02-21
The obligatory round of post-major-release bugfixes.
:bug: Fixes
These issues were regressions.
- #3754: Mocha again finds test.jswhen run without arguments (@plroebuck)
- #3756: Mocha again supports third-party interfaces via --ui(@boneskull)
- #3755: Fix broken --watch(@boneskull)
- #3759: Fix unwelcome deprecation notice when Mocha run against languages (CoffeeScript) with implicit return statements; returning a non-undefinedvalue from adescribecallback is no longer considered deprecated (@boneskull)
:book: Documentation
6.0.0 / 2019-02-18
:tada: Enhancements
:bug: Fixes
- #3737: Fix falsy values from options globals (@plroebuck)
- #3707: Fix encapsulation issues for Suite#_onlyTestsandSuite#_onlySuites(@vkarpov15)
- #3711: Fix diagnostic messages dealing with plurality and markup of output (@plroebuck)
- #3723: Fix "reporter-option" to allow comma-separated options (@boneskull)
- #3722: Fix code quality and performance of lookupFilesandfiles(@plroebuck)
- #3650, #3654: Fix noisy error message when no files found (@craigtaub)
- #3632: Tests having an empty title are no longer confused with the "root" suite (@juergba)
- #3666: Fix missing error codes (@vkarpov15)
- #3684: Fix exiting problem in Node.js v11.7.0+ (@addaleax)
- #3691: Fix --delay(and other boolean options) not working in all cases (@boneskull)
- #3692: Fix invalid command-line argument usage not causing actual errors (@boneskull)
- #3698, #3699: Fix debug-related Node.js options not working in all cases (@boneskull)
- #3700: Growl notifications now show the correct number of tests run (@outsideris)
- #3686: Avoid potential ReDoS when diffing large objects (@cyjake)
- #3715: Fix incorrect order of emitted events when used programmatically (@boneskull)
- #3706: Fix regression wherein --reporter-option/--reporter-optionsdid not support comma-separated key/value pairs (@boneskull)
:book: Documentation
:nut_and_bolt: Other
6.0.0-1 / 2019-01-02
:bug: Fixes
- Fix missing mocharc.jsonin published package (@boneskull)
6.0.0-0 / 2019-01-01
Documentation for this release can be found at next.mochajs.org!
Welcome @plroebuck, @craigtaub, & @markowsiak to the team!
:boom: Breaking Changes
- #3149: Drop Node.js v4.x support (@outsideris)
- #3556: Changes to command-line options (@boneskull):
- --grepand- --fgrepare now mutually exclusive; attempting to use both will cause Mocha to fail instead of simply ignoring- --grep
- --compilersis no longer supported; attempting to use will cause Mocha to fail with a link to more information
- -dis no longer an alias for- --debug;- -dis currently ignored
- #3275: --watch-extensionsno longer impliesjs; it must be explicitly added (@TheDancingCode)
 
- #2908: tapreporter emits error messages (@chrmod)
- #2819: When conditionally skipping in a beforehook, subsequentbeforehooks and tests in nested suites are now skipped (@bannmoore)
- #627: Emit filepath in "timeout exceeded" exceptions where applicable (@boneskull)
- #3556: lib/template.htmlhas moved tolib/browser/template.html(@boneskull)
- #2576: An exception is now thrown if Mocha fails to parse or find a mocha.optsat a user-specified path (@plroebuck)
- #3458: Instantiating a Base-extending reporter without aRunnerparameter will throw an exception (@craigtaub)
- #3125: For consumers of Mocha's programmatic API, all exceptions thrown from Mocha now have a codeproperty (and some will have additional metadata). SomeErrormessages have changed. Please use thecodeproperty to checkErrortypes instead of themessageproperty; these descriptions will be localized in the future. (@craigtaub)
:fax: Deprecations
These are soft-deprecated, and will emit a warning upon use. Support will be removed in (likely) the next major version of Mocha:
- -gcusers should use- --gc-globalinstead
- Consumers of the function exported by bin/optionsshould now use theloadMochaOptsorloadOptions(preferred) functions exported by thelib/cli/optionsmodule
Regarding the Mocha class constructor (from lib/mocha):
- Use property color: falseinstead ofuseColors: false
- Use property timeout: falseinstead ofenableTimeouts: false
All of the above deprecations were introduced by #3556.
mocha.opts is now considered "legacy"; please prefer RC file or package.json over mocha.opts.
:tada: Enhancements
Enhancements introduced in #3556:
- Mocha now supports "RC" files in JS, JSON, YAML, or - package.json-based (using- mochaproperty) format
 - 
- .mocharc.js,- .mocharc.json,- .mocharc.yamlor- .mocharc.ymlare valid "rc" file names and will be automatically loaded
- Use --config /path/to/rc/fileto specify an explicit path
- Use --package /path/to/package.jsonto specify an explicitpackage.jsonto read themochaprop from
- Use --no-configor--no-packageto completely disable loading of configuration via RC file andpackage.json, respectively
- Configurations are merged as applicable using the priority list:
- Command-line arguments
- RC file
- package.json
- mocha.opts
- Mocha's own defaults
 
- Check out these example config files
 
- Node/V8 flag support in - mochaexecutable:
 - 
- Support all allowed nodeflags as supported by the running version ofnode(also thanks to @demurgos)
- Support any V8 flag by prepending --v8-to the flag name
- All flags are also supported via config files, package.jsonproperties, ormocha.opts
- Debug-related flags (e.g., --inspect) now imply--no-timeouts
- Use of e.g., --debugwill automatically invoke--inspectif supported by running version ofnode
 
- Support negation of any Mocha-specific command-line flag by prepending - --no-to the flag name
 
- Interfaces now have descriptions when listed using - --interfacesflag
 
- Mochaconstructor supports all options
 
- --extensionis now an alias for- --watch-extensionsand affects non-watch-mode test runs as well. For example, to run only- test/*.coffee(not- test/*.js), you can do- mocha --require coffee-script/register --extensions coffee.
 
- #3552: - tapreporter is now TAP13-capable (@plroebuck & @mollstam)
 
- #3535: Mocha's version can now be queried programmatically via public property - Mocha.prototype.version(@plroebuck)
 
- #3428: - xunitreporter shows diffs (@mlucool)
 
- #2529: - Runnernow emits a- retryevent when tests are retried (reporters can listen for this) (@catdad)
 
- #2962, #3111: In-browser notification support; warn about missing prereqs when - --growlsupplied (@plroebuck)
 
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
5.2.0 / 2018-05-18
:tada: Enhancements
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
5.1.1 / 2018-04-18
:bug: Fixes
5.1.0 / 2018-04-12
:tada: Enhancements
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
5.0.5 / 2018-03-22
Welcome @outsideris to the team!
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
5.0.4 / 2018-03-07
:bug: Fixes
- #3265: Fixes regression in "watch" functionality introduced in v5.0.2 (@outsideris)
5.0.3 / 2018-03-06
This patch features a fix to address a potential "low severity" ReDoS vulnerability in the diff package (a dependency of Mocha).
:lock: Security Fixes
:nut_and_bolt: Other
5.0.2 / 2018-03-05
This release fixes a class of tests which report as false positives. Certain tests will now break, though they would have previously been reported as passing. Details below. Sorry for the inconvenience!
:bug: Fixes
- #3226: Do not swallow errors that are thrown asynchronously from passing tests (@boneskull). Example: - ```js
it('should actually fail, sorry!', function (done) {
// passing assertion
assert(true === true); - // test complete & is marked as passing
done(); - // ...but something evil lurks within
setTimeout(() => {
throw new Error('chaos!');
}, 100);
});
``` - Previously to this version, Mocha would have silently swallowed the - chaos!exception, and you wouldn't know. Well, now you know. Mocha cannot recover from this gracefully, so it will exit with a nonzero code.
 - Maintainers of external reporters: If a test of this class is encountered, the - Runnerinstance will emit the- endevent twice; you may need to change your reporter to use- runner.once('end')intead of- runner.on('end').
 
- #3093: Fix stack trace reformatting problem (@outsideris) 
:nut_and_bolt: Other
5.0.1 / 2018-02-07
...your garden-variety patch release.
Special thanks to Wallaby.js for their continued support! :heart:
:bug: Fixes
:book: Documentation
:nut_and_bolt: Other
5.0.0 / 2018-01-17
Mocha starts off 2018 right by again dropping support for unmaintained rubbish.
Welcome @vkarpov15 to the team!
:boom: Breaking Changes
- #3148: Drop support for IE9 and IE10 (@Bamieh)
Practically speaking, only code which consumes (through bundling or otherwise) the userland buffer module should be affected. However, Mocha will no longer test against these browsers, nor apply fixes for them.
:tada: Enhancements
:bug: Fixes
:sunglasses: Developer Experience
:book: Documentation
:nut_and_bolt: Other