LOADASH Cheat Sheet

Lodash cheatsheet

Excerpt

This is not a complete list. · One-page guide to Lodash

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#Collections

Finding

_.filter(list, (n) => n % 2)    
_.find(list, (n) => n % 2)      
_.findLast(list, ...)           

Works for both arrays and objects.

Accessing

_.at([ abcd ], 0)               
_.at([ abcd ], [ 0, 1 ])        

Set/get

_.set(object, 'users[0].name', value)
_.get(object, 'users[0].name')
_.get(object, ['users', 0, 'name'])

Iteration

_.forEach(list, (item, i) => ...)
_.forEachRight(list, ...)

_.map(list, ...)

_.every(users, (u) => u.active)  
_.any(users, ...)                

#Array

Arrays

_.chunk([ abcd ], 2)           
_.compact(list)

_.fill(Array(4), 'x')          
_.flatten
_.flattenDeep

Filtering

_.drop([ abcdef ], 2)          
_.dropRight([ abcdef ], 2)     
_.take([ abcdef ], 2)          
_.takeRight([ abcdef ], 2)     
_.slice([ abcdef ], 2, 4)      

_.initial([ abcdef ])          
_.rest([ abcdef ])             

_.dropWhile(list, 'active')            
_.dropWhile(list, 'active', true)
_.dropWhile(list, { active: true })
_.dropWhile(list, (n) => ...)
_.dropRightWhile(list, ...)

_.without([ abcde ], b)        

_.remove(list, (n) => n % 2)

Accessing

_.first([ abcdef ])            
_.last([ abcdef ])             

Sets

_.uniq()
_.difference([ abc ], [ bc ])       
_.intersection([ abc ], [ bcd ])    
_.union([ abc ], [ bcd ])           

Array#concat()

Indexes

_.findIndex(list, fn)
_.findLastIndex(list, fn)

_.sortedIndex(list, val)
_.sortedLastIndex(list, val)

_.indexOf(list, val)

#Functions

Currying

greet = (greeting, name) => `${greeting}, ${name}!`

fn = _.partial(fn, 'hi')
fn('joe')    

fn = _.partial(fn, 'joe')
fn('yo')     

_.curry(greet)('hi')         
_.curryRight(greet)('joe')   

#Decorating functions

Throttling

_.throttle(fn)
_.debounce(fn)

Limiting

_.before(5, fn)         
_.after(5, fn)          
_.once(fn)              

Etc

_.wrap(_.escape, (name) => `hi ${name}`)


_.delay(fn, 2000)

_.negate(fn)

_.memoize(fn)
_.memoize(fn, ...)

#Strings

Capitalization

_.capitalize('hello world')   
_.startCase('hello_world')    
_.snakeCase('hello world')    
_.kebabCase('hello world')    
_.camelCase('hello world')    

Padding

_.pad('abc', 3)           
_.pad('abc', 8)           
_.pad('abc', 8, '_-')     
_.padStart('abc', 3)      
_.padStart('abc', 6)      
_.padStart('abc', 6, '_-')
_.padEnd('abc', 3)        
_.padEnd('abc', 6)        
_.padEnd('abc', 6, '_-')  

Trim

_.trim('  str  ')         
_.trimLeft('  str  ')     
_.trimRight('  str  ')    

Etc

_.repeat('-', 2)              
_.deburr('déjà vu')           
_.trunc('hello world', 5)     

_.startsWith('abc', 'a')   
_.endsWith('abc', 'c')     

#Objects

Keys and values

_.keys(obj)
_.values(obj)

#Chaining

Chain and value

_([1, 2, 3])
  .reduce((total, n) => total + n)
  .map((n) => n * n)
  .tap(console.log)
  .thru((n) => n.reverse())
  .value()