Show Menu
Cheatography
  1. Home >
  2. Programming >

Essential Vanilla JavaScript Methods Cheat Sheet by

Iterating

for (key in obj)
Iterates over keys
for (value of obj)
Iterates over values

Array Methods

arr.f­or­Eac­h(f­unc­tio­n(val, I, arr))
Executes a function for each value.
arr.e­ve­ry(­fun­cti­on(val, i, arr))
Returns true if every value passes the function test
arr.r­ev­erse()
Reverses the original array
Sear­ching
arr.i­nc­lud­es(val)
Returns true if array contains a value
arr.i­nd­exO­f(val)
Returns the index of a value in an array or -1 if not found
arr.f­in­d(f­unc­tion)
Returns the value of the first index to satisfy the function
arr.f­in­dIn­dex­(fu­nction)
Returns the index of the first value to satisfy the function
Add Values
arr.s­pl­ice­(start, 0, items...)
Adds items to array beginning at starting index
arr.u­ns­hif­t(val)
Adds val to front of array
arr.p­us­h(val)
Adds val to back of array
Delete Values
arr.s­­p­lic­e(s­tart, n)
Delete n items from array beginning at starting index
arr.s­hift()
Removes arr[0] and returns the value
arr.p­op()
Removes last value in a array and returns it
Copy Values
arr.s­li­ce(­beg, end)
Returns a shallow copy of arr from beg to end (non-i­ncl­usive)
To String
arr.j­oi­n(­sep­ara­tor)
Returns a string from the array values, with an optional separator string
JSON.s­tri­ngi­fy(arr)
Returns a JSON string repres­ent­ation of array. Deep string.
arr.t­oS­tring()
Returns a comma-­del­imited string of scalar array values. Shallow string.
Sort­ing
arr.s­ort()
Sorts lexico­gra­phi­cally
arr.s­or­t((a, b) => a - b)
Sorts numbers

Number Methods

num.t­oF­ixe­d(n)
Returns a number rounded to n signif­icant figures after the decimal
num.t­oP­rec­isi­on(n)
Returns a string rounded to n signif­icant figures
num.t­oS­tring()
Returns a string repres­ent­ation of a number
 

Object Methods

Object to Array
Object.ke­ys(obj)
Array of obj keys
Object.va­lue­s(obj)
Array of obj values
Object.en­tri­es(obj)
2D array of key:value pairs
Object to String
JSON.s­tri­ngi­fy(obj)
obj to string
JSON.p­ars­e(obj)
string to obj
Add/­Remove Proper­ties
delete obj[key]
Delete property
obj[key] = value
Add property

String methods

str.s­li­ce(­beg, end)
returns a substring from beginning to end index
str.t­oL­owe­rCase()
Returns a lowercase version of str
String to Array
str.s­pl­it(­sep­arator)
Returns an array of the string, split by the separator
Sear­ching Strings
str.i­nc­lud­es(str)
Returns true if str is in string
str.i­nd­exO­f(str)
Returns index of str if within string, or -1 otherwise
str.s­ta­rts­Wit­h(str, beg)
Returns true if string starts with str, optionally from beg index.
str.e­nd­sWi­th(str, len)
Returns true if string starts with str, optionally limited to the first len characters
Combine Strings
str.c­on­cat­(st­rin­gs...)
Returns new string concat­enation

Math Object Methods

Math.a­bs(­num)
Returns the absolute value of num
Random Numbers
Math.r­oun­d(M­ath.ra­ndom() * (max - min)) + min)
Returns a random number between two ints
Math.r­andom()
Returns a random number between 0 and 1.
Roun­ding
Math.f­loo­r(­num)
Goes down to the nearest int <= num
Math.c­eil­(num)
Goes up to the nearest int >= num
Math.r­oun­d(­num)
Rounds to the nearest int
           

Help Us Go Positive!

We offset our carbon usage with Ecologi. Click the link below to help us!

We offset our carbon footprint via Ecologi
 

Metadata

  • Languages:
  • Published: 29th May, 2018
  • Rated: 5 stars based on 2 ratings

Favourited By

albinotonnina Lavysh

Comments

No comments yet. Add yours below!

Add a Comment

Your Comment

Please enter your name.

    Please enter your email address

      Please enter your Comment.

          Related Cheat Sheets

          JavaScript Cheat Sheet
          CoffeeScript language Cheat Sheet
          C Reference Cheat Sheet