highdash

A small utility library inspired by Lodash

Why does this exist?

There are some high level goals for this repo;

• To show that you might not need to import Lodash to achieve your goals
• A method for me to learn how some of these functions actually work
• This isn't meant to be a complete replacement for every Lodash function
• Each function is intentionally a smaller, easier-to-read subset rather than a full Lodash clone
• Lodash doesn't treat each function in isolation, this library does for easy copy & pasting
  • Lodash re-uses a lot of functions as helpers or uses it's own collection of helpers, obscuring what the function is actually doing
  • This should mean that each function in this library should be copy-pasteable
  • This is also only achieved if each function is dependency free (even at the cost of duplication of logic)
• To use TypeScript to describe the supported inputs clearly, without pretending each function handles every edge case Lodash does

Project philosophy

This library is not trying to become a line-for-line Lodash replacement.

The bar for each function is:

• You should be able to read the whole implementation quickly and understand how it works
• The supported behavior should be obvious from the code, tests, and types
• Correctness bugs in the supported scope should be fixed
• Complexity should only be added when it pays for itself in readability and confidence

That means:

• Prefer a smaller, explicit feature set over broad Lodash-style compatibility
• Prefer honest types over very wide overloads that suggest unsupported behavior
• Prefer tests that document intended behavior over tests that only chase parity
• Avoid deep helper systems that make individual utilities harder to understand
• Be explicit about supported shapes when a utility is intentionally narrow, such as merge only supporting arrays and plain objects

TypeScript style

Type parameter names should describe what they represent.

Good examples:

• ArrayItem
• CollectionItem
• FunctionArguments
• ReturnedValue

Avoid single-letter names such as T, R, or P when a descriptive name would make the function easier to read.

Why no barrel imports?

While bundling the code for the browser, tree-shaking of libraries such as Lodash happens automatically. However, testing frameworks such as Jest don't do this tree-shaking by design. This means that Jest will load the entire library (such as Lodash) into memory for each test file, using a lot of memory and causing slower tests.

In practise, removing barrel imports halved the run time of tests at my company despite the codebase increasing in size by 40%.

Function list

Function	Version exists?
(Array) _.chunk	/src/chunk/chunk.ts
(Array) _.compact	/src/compact/compact.ts
(Array) _.concat	/src/concat/concat.ts
(Array) _.difference	/src/difference/difference.ts
(Array) _.differenceBy	/src/differenceBy/differenceBy.ts
(Array) _.differenceWith	/src/differenceWith/differenceWith.ts
(Array) _.drop	/src/drop/drop.ts
(Array) _.dropRight	/src/dropRight/dropRight.ts
(Array) _.dropRightWhile	❌
(Array) _.dropWhile	❌
(Array) _.fill	❌
(Array) _.findIndex	/src/findIndex/findIndex.ts
(Array) _.findLastIndex	❌
(Array) _.first -> head	/src/head/head.ts
(Array) _.flatten	/src/flatten/flatten.ts
(Array) _.flattenDeep	/src/flattenDeep/flattenDeep.ts
(Array) _.flattenDepth	/src/flattenDepth/flattenDepth.ts
(Array) _.fromPairs	/src/fromPairs/fromPairs.ts
(Array) _.head	/src/head/head.ts
(Array) _.indexOf	/src/indexOf/indexOf.ts
(Array) _.initial	❌
(Array) _.intersection	/src/intersection/intersection.ts
(Array) _.intersectionBy	❌
(Array) _.intersectionWith	❌
(Array) _.join	❌
(Array) _.last	/src/last/last.ts
(Array) _.lastIndexOf	❌
(Array) _.nth	/src/nth/nth.ts
(Array) _.pull	❌
(Array) _.pullAll	❌
(Array) _.pullAllBy	❌
(Array) _.pullAllWith	❌
(Array) _.pullAt	❌
(Array) _.remove	❌
(Array) _.reverse	❌
(Array) _.slice	❌
(Array) _.sortedIndex	❌
(Array) _.sortedIndexBy	❌
(Array) _.sortedIndexOf	❌
(Array) _.sortedLastIndex	❌
(Array) _.sortedLastIndexBy	❌
(Array) _.sortedLastIndexOf	❌
(Array) _.sortedUniq	❌
(Array) _.sortedUniqBy	❌
(Array) _.tail	/src/tail/tail.ts
(Array) _.take	/src/take/take.ts
(Array) _.takeRight	/src/takeRight/takeRight.ts
(Array) _.takeRightWhile	❌
(Array) _.takeWhile	❌
(Array) _.union	/src/union/union.ts
(Array) _.unionBy	❌
(Array) _.unionWith	❌
(Array) _.uniq	/src/uniq/uniq.ts
(Array) _.uniqBy	❌
(Array) _.uniqWith	❌
(Array) _.unzip	❌
(Array) _.unzipWith	❌
(Array) _.without	/src/without/without.ts
(Array) _.xor	❌
(Array) _.xorBy	❌
(Array) _.xorWith	❌
(Array) _.zip	❌
(Array) _.zipObject	❌
(Array) _.zipObjectDeep	❌
(Array) _.zipWith	❌
(Collection) _.countBy	❌
(Collection) _.each -> forEach	❌
(Collection) _.eachRight -> forEachRight	❌
(Collection) _.every	/src/every/every.ts
(Collection) _.filter	/src/filter/filter.ts
(Collection) _.find	/src/find/find.ts
(Collection) _.findLast	❌
(Collection) _.flatMap	❌
(Collection) _.flatMapDeep	❌
(Collection) _.flatMapDepth	❌
(Collection) _.forEach	❌
(Collection) _.forEachRight	❌
(Collection) _.groupBy	/src/groupBy/groupBy.ts
(Collection) _.includes	/src/includes/includes.ts
(Collection) _.invokeMap	❌
(Collection) _.keyBy	❌
(Collection) _.map	/src/map/map.ts
(Collection) _.orderBy	❌
(Collection) _.partition	❌
(Collection) _.reduce	❌
(Collection) _.reduceRight	❌
(Collection) _.reject	❌
(Collection) _.sample	❌
(Collection) _.sampleSize	❌
(Collection) _.shuffle	❌
(Collection) _.size	/src/size/size.ts
(Collection) _.some	/src/some/some.ts
(Collection) _.sortBy	/src/sortBy/sortBy.ts
(Date) _.now	❌
(Function) _.after	❌
(Function) _.ary	❌
(Function) _.before	❌
(Function) _.bind	❌
(Function) _.bindKey	❌
(Function) _.curry	❌
(Function) _.curryRight	❌
(Function) _.debounce	❌
(Function) _.defer	❌
(Function) _.delay	❌
(Function) _.flip	❌
(Function) _.memoize	/src/memoize/memoize.ts
(Function) _.negate	❌
(Function) _.once	/src/once/once.ts
(Function) _.overArgs	❌
(Function) _.partial	❌
(Function) _.partialRight	❌
(Function) _.rearg	❌
(Function) _.rest	❌
(Function) _.spread	❌
(Function) _.throttle	/src/throttle/throttle.ts
(Function) _.unary	❌
(Function) _.wrap	❌
(Lang) _.castArray	/src/castArray/castArray.ts
(Lang) _.clone	❌
(Lang) _.cloneDeep	/src/cloneDeep/cloneDeep.ts
(Lang) _.cloneDeepWith	❌
(Lang) _.cloneWith	❌
(Lang) _.conformsTo	❌
(Lang) _.eq	❌
(Lang) _.gt	❌
(Lang) _.gte	❌
(Lang) _.isArguments	❌
(Lang) _.isArray	❌
(Lang) _.isArrayBuffer	❌
(Lang) _.isArrayLike	❌
(Lang) _.isArrayLikeObject	❌
(Lang) _.isBoolean	❌
(Lang) _.isBuffer	❌
(Lang) _.isDate	❌
(Lang) _.isElement	❌
(Lang) _.isEmpty	/src/isEmpty/isEmpty.ts
(Lang) _.isEqual	/src/isEqual/isEqual.ts
(Lang) _.isEqualWith	❌
(Lang) _.isError	❌
(Lang) _.isFinite	❌
(Lang) _.isFunction	❌
(Lang) _.isInteger	❌
(Lang) _.isLength	❌
(Lang) _.isMap	❌
(Lang) _.isMatch	❌
(Lang) _.isMatchWith	❌
(Lang) _.isNaN	❌
(Lang) _.isNative	❌
(Lang) _.isNil	❌
(Lang) _.isNull	❌
(Lang) _.isNumber	❌
(Lang) _.isObject	❌
(Lang) _.isObjectLike	❌
(Lang) _.isPlainObject	❌
(Lang) _.isRegExp	❌
(Lang) _.isSafeInteger	❌
(Lang) _.isSet	❌
(Lang) _.isString	❌
(Lang) _.isSymbol	❌
(Lang) _.isTypedArray	❌
(Lang) _.isUndefined	❌
(Lang) _.isWeakMap	❌
(Lang) _.isWeakSet	❌
(Lang) _.lt	❌
(Lang) _.lte	❌
(Lang) _.toArray	❌
(Lang) _.toFinite	❌
(Lang) _.toInteger	❌
(Lang) _.toLength	❌
(Lang) _.toNumber	❌
(Lang) _.toPlainObject	❌
(Lang) _.toSafeInteger	❌
(Lang) _.toString	❌
(Math) _.add	❌
(Math) _.ceil	❌
(Math) _.divide	❌
(Math) _.floor	❌
(Math) _.max	❌
(Math) _.maxBy	❌
(Math) _.mean	❌
(Math) _.meanBy	❌
(Math) _.min	❌
(Math) _.minBy	❌
(Math) _.multiply	❌
(Math) _.round	❌
(Math) _.subtract	❌
(Math) _.sum	❌
(Math) _.sumBy	❌
(Number) _.clamp	❌
(Number) _.inRange	❌
(Number) _.random	❌
(Object) _.assign	❌
(Object) _.assignIn	❌
(Object) _.assignInWith	❌
(Object) _.assignWith	❌
(Object) _.at	❌
(Object) _.create	❌
(Object) _.defaults	❌
(Object) _.defaultsDeep	❌
(Object) _.entries -> toPairs	❌
(Object) _.entriesIn -> toPairsIn	❌
(Object) _.extend -> assignIn	❌
(Object) _.extendWith -> assignInWith	❌
(Object) _.findKey	❌
(Object) _.findLastKey	❌
(Object) _.forIn	❌
(Object) _.forInRight	❌
(Object) _.forOwn	❌
(Object) _.forOwnRight	❌
(Object) _.functions	❌
(Object) _.functionsIn	❌
(Object) _.get	❌
(Object) _.has	/src/has/has.ts
(Object) _.hasIn	❌
(Object) _.invert	❌
(Object) _.invertBy	❌
(Object) _.invoke	❌
(Object) _.keys	/src/keys/keys.ts
(Object) _.keysIn	❌
(Object) _.mapKeys	❌
(Object) _.mapValues	❌
(Object) _.merge	/src/merge/merge.ts
(Object) _.mergeWith	❌
(Object) _.omit	❌
(Object) _.omitBy	❌
(Object) _.pick	/src/pick/pick.ts
(Object) _.pickBy	❌
(Object) _.result	❌
(Object) _.set	❌
(Object) _.setWith	❌
(Object) _.toPairs	/src/toPairs/toPairs.ts
(Object) _.toPairsIn	❌
(Object) _.transform	❌
(Object) _.unset	❌
(Object) _.update	❌
(Object) _.updateWith	❌
(Object) _.values	/src/values/values.ts
(Object) _.valuesIn	❌
(String) _.camelCase	/src/camelCase/camelCase.ts
(String) _.capitalize	/src/capitalize/capitalize.ts
(String) _.deburr	/src/deburr/deburr.ts
(String) _.endsWith	/src/endsWith/endsWith.ts
(String) _.escape	/src/escape/escape.ts
(String) _.escapeRegExp	/src/escapeRegExp/escapeRegExp.ts
(String) _.kebabCase	/src/kebabCase/kebabCase.ts
(String) _.lowerCase	/src/lowerCase/lowerCase.ts
(String) _.lowerFirst	/src/lowerFirst/lowerFirst.ts
(String) _.pad	/src/pad/pad.ts
(String) _.padEnd	/src/padEnd/padEnd.ts
(String) _.padStart	/src/padStart/padStart.ts
(String) _.parseInt	/src/parseInt/parseInt.ts
(String) _.repeat	/src/repeat/repeat.ts
(String) _.replace	/src/replace/replace.ts
(String) _.snakeCase	/src/snakeCase/snakeCase.ts
(String) _.split	/src/split/split.ts
(String) _.startCase	/src/startCase/startCase.ts
(String) _.startsWith	/src/startsWith/startsWith.ts
(String) _.template	❌
(String) _.toLower	/src/toLower/toLower.ts
(String) _.toUpper	/src/toUpper/toUpper.ts
(String) _.trim	/src/trim/trim.ts
(String) _.trimEnd	/src/trimEnd/trimEnd.ts
(String) _.trimStart	/src/trimStart/trimStart.ts
(String) _.truncate	/src/truncate/truncate.ts
(String) _.unescape	/src/unescape/unescape.ts
(String) _.upperCase	/src/upperCase/upperCase.ts
(String) _.upperFirst	/src/upperFirst/upperFirst.ts
(String) _.words	/src/words/words.ts
(Util) _.attempt	❌
(Util) _.bindAll	❌
(Util) _.cond	❌
(Util) _.conforms	❌
(Util) _.constant	/src/constant/constant.ts
(Util) _.defaultTo	/src/defaultTo/defaultTo.ts
(Util) _.flow	❌
(Util) _.flowRight	❌
(Util) _.identity	/src/identity/identity.ts
(Util) _.iteratee	❌
(Util) _.matches	❌
(Util) _.matchesProperty	❌
(Util) _.method	❌
(Util) _.methodOf	❌
(Util) _.mixin	❌
(Util) _.noConflict	❌
(Util) _.noop	/src/noop/noop.ts
(Util) _.nthArg	❌
(Util) _.over	❌
(Util) _.overEvery	❌
(Util) _.overSome	❌
(Util) _.property	❌
(Util) _.propertyOf	❌
(Util) _.range	/src/range/range.ts
(Util) _.rangeRight	❌
(Util) _.runInContext	❌
(Util) _.stubArray	❌
(Util) _.stubFalse	❌
(Util) _.stubObject	❌
(Util) _.stubString	❌
(Util) _.stubTrue	❌
(Util) _.times	❌
(Util) _.toPath	❌
(Util) _.uniqueId	❌