223 lines
3.7 KiB
Markdown
223 lines
3.7 KiB
Markdown
---
|
|
title: Lodash
|
|
category: JavaScript libraries
|
|
---
|
|
|
|
> This is an incomplete list.
|
|
|
|
## Collections
|
|
|
|
Works for both arrays and objects.
|
|
|
|
```js
|
|
_.filter(list, (n) => n % 2) //=> Array
|
|
_.find(list, (n) => n % 2) //=> item
|
|
_.findRight(list, ...) //=> item
|
|
```
|
|
|
|
### Accessing
|
|
|
|
```js
|
|
_.at([ abcd ], 0) //=> [ a ] - same as list[0]
|
|
_.at([ abcd ], [ 0, 1 ]) //=> [ ab ]
|
|
```
|
|
|
|
### Set/get
|
|
|
|
```js
|
|
_.set(object, 'users[0].name', value)
|
|
_.get(object, 'users[0].name')
|
|
_.get(object, ['users', 0, 'name'])
|
|
```
|
|
|
|
### Iteration
|
|
|
|
```js
|
|
_.forEach(list, (item, i) => ...)
|
|
_.forEachRight(list, ...)
|
|
|
|
_.map(list, ...)
|
|
```
|
|
|
|
```js
|
|
_.every(users, (u) => u.active) //=> true|false (aka _.all)
|
|
_.any(users, ...) //=> true|false (aka _.some)
|
|
```
|
|
|
|
## Array
|
|
|
|
```js
|
|
_.chunk([ abcd ], 2) //=> [ [ab], [cd] ]
|
|
_.compact(list)
|
|
|
|
_.fill(Array(4), 'x') //=> [ 'x', 'x', 'x', 'x' ]
|
|
_.flatten
|
|
_.flattenDeep
|
|
```
|
|
|
|
### Filtering
|
|
|
|
```js
|
|
_.drop([ abcdef ], 2) //=> [ cdef ]
|
|
_.dropRight([ abcdef ], 2) //=> [ abcd ]
|
|
_.take([ abcdef ], 2) //=> [ ab ]
|
|
_.takeRight([ abcdef ], 2) //=> [ de ]
|
|
|
|
_.initial([ abcdef ]) //=> [ abcde ] - dropRight(list, 1)
|
|
_.rest([ abcdef ]) //=> [ bcdef ] - takeRight(list, 1)
|
|
|
|
_.slice([ abcdef ], 2, 4) //=> [ cd ]
|
|
|
|
_.dropWhile(list, 'active') // works like filter
|
|
_.dropWhile(list, 'active', true)
|
|
_.dropWhile(list, { active: true })
|
|
_.dropWhile(list, (n) => ...)
|
|
_.dropRightWhile(list, ...)
|
|
|
|
_.without([ abcde ], b) //=> [ acde ]
|
|
|
|
_.remove(list, (n) => n % 2)
|
|
```
|
|
|
|
### Accessing
|
|
|
|
```js
|
|
_.first([ abcdef ]) //=> a
|
|
_.last([ abcdef ]) //=> f
|
|
```
|
|
|
|
### Sets
|
|
|
|
```
|
|
_.uniq()
|
|
_.difference([ abc ], [ bc ]) //=> [ a ]
|
|
_.intersection([ abc ], [ bcd ]) //=> [ bc ]
|
|
_.union([ abc ], [ bcd ]) //=> [ abcd ] (unique)
|
|
|
|
Array#concat()
|
|
```
|
|
|
|
### Indexes
|
|
|
|
```
|
|
_.findIndex
|
|
_.findLastIndex
|
|
|
|
_.sortedIndex(list, val)
|
|
_.sortedLastIndex(list, val)
|
|
|
|
_.indexOf(list, val)
|
|
```
|
|
|
|
## Functions
|
|
|
|
### Currying
|
|
|
|
```js
|
|
greet = (greeting, name) => `${greeting}, ${name}!`
|
|
```
|
|
|
|
```js
|
|
fn = _.partial(fn, 'hi')
|
|
fn('joe') //=> 'hi, joe!'
|
|
|
|
_.partial(fn, 'joe')
|
|
fn('yo') //=> 'yo, joe!'
|
|
```
|
|
|
|
```js
|
|
_.curry(greet)('hi') //=> function(name)
|
|
_.curryRight(greet)('joe') //=> function(greet)
|
|
```
|
|
|
|
## Functions - decorating
|
|
|
|
### Throttling
|
|
|
|
```js
|
|
_.throttle(fn)
|
|
_.debounce(fn)
|
|
```
|
|
|
|
### Limiting
|
|
|
|
```js
|
|
_.before(5, fn) // only works 5 times
|
|
_.after(5, fn) // works only after 5 times
|
|
_.once(fn) // like _.before(fn, 1)
|
|
```
|
|
|
|
### Etc
|
|
|
|
```js
|
|
_.wrap(_.escape, (name) => `hi ${name}`)
|
|
// same as doing `name = _.escape(name)`
|
|
|
|
_.delay(fn, 2000)
|
|
|
|
_.negate(fn)
|
|
|
|
_.memoize(fn)
|
|
_.memoize(fn, ...)
|
|
```
|
|
|
|
## Strings
|
|
|
|
### Capitalization
|
|
|
|
```js
|
|
_.capitalize('hello world') //=> 'Hello world'
|
|
_.startCase('hello_world') //=> 'Hello World'
|
|
_.snakeCase('hello world') //=> 'hello_world'
|
|
_.kebabCase('hello world') //=> 'hello-world'
|
|
_.camelCase('hello world') //=> 'helloWorld'
|
|
```
|
|
|
|
### Padding
|
|
|
|
```js
|
|
_.pad('abc', 8) //=> ' abc '
|
|
_.padLeft('abc', 8) //=> ' abc'
|
|
_.padLeft('abc', 8, '-') //=> '00000abc'
|
|
_.padRight(...)
|
|
```
|
|
|
|
### Trim
|
|
|
|
```js
|
|
_.trim(' str ')
|
|
_.trimLeft(' str ')
|
|
_.trimRight(' str ')
|
|
```
|
|
|
|
### Etc
|
|
|
|
```js
|
|
_.repeat('-', 2) //=> '--'
|
|
_.deburr('déjà vu') //=> 'deja vu'
|
|
_.trunc('hello world', 5) //=> 'hello...'
|
|
```
|
|
|
|
```js
|
|
_.startsWith('abc', 'a') //=> true
|
|
_.endsWith('abc', 'c') //=> true
|
|
```
|
|
|
|
## Objects
|
|
|
|
```js
|
|
_.keys(obj)
|
|
_.values(obj)
|
|
```
|
|
|
|
## Chaining
|
|
|
|
```js
|
|
_([1, 2, 3])
|
|
.reduce((total, n) => total + n)
|
|
.map((n) => n * n)
|
|
.tap(console.log)
|
|
.thru((n) => n.reverse())
|
|
.value()
|
|
```
|