Things you can do with Arrays

#javascript #webdev #arrays #math

Get average value of items in a javascript array

const arrAvg = arr => arr.reduce((a,b) => a + b, 0) / arr.length
// arrAvg([20, 10, 5, 10]) -> 11.25

#javascript #nodejs

Append a Value to an Array

db.students.update(
   { _id: 1 },
   { $push: { scores: 89 } }
)

How to Access Clicked Element From an Array With the Same Class

var allActionButtons = document.getElementsByClassName("action-buttons");

for (var i = 0; i < allActionButtons.length; i++) {

  allActionButtons[i].addEventListener('click', functionToRunWhenClicked, false);

}

var functionToRunWhenClicked = function {
  // Add some stuff here
}

#javascript #webdev #arrays #math

Function to find the minimum value in Javascript Arrays

const arrMin = arr => Math.min(...arr);
// arrMin([20, 10, 5, 10]) -> 5

#javascript #webdev #javascript #arrays #math

Function to find maximum value in javascript array

const arrMax = arr => Math.max(...arr);
// arrMax([20, 10, 5, 10]) -> 20

#javascript #webdev #arrays #math

Get sum of all values in javascript array

const arrSum = arr => arr.reduce((a,b) => a + b, 0)
// arrSum([20, 10, 5, 10]) -> 45

#javascript #mongoose #mongodb #mean

mongodb - How to find items using regex in Mongoose for partial text search

   var Person = mongoose.model('Person', yourSchema);
   // find each person with a name contains 'Ghost'
   Person.findOne({ "name" : { $regex: /Ghost/, $options: 'i' } },
          function (err, person) {
                 if (err) return handleError(err);
                 console.log('%s %s is a %s.', person.name.first, person.name.last, person.occupation);

   });

Similiar Collections

String Magic

@frogblog #javascript

How to Get the Domain From A URL Using Javascript Capitalize the first letter of a String Check String contains Substring Method

Things you can do with Arrays

@mishka #javascript

Get average value of items in a javascript array Append a Value to an Array How to Access Clicked Element From an Array With the Same Class Function to find the minimum value in Javascript Arrays Function to find maximum value in javascript array Get sum of all values in javascript array mongodb - How to find items using regex in Mongoose for partial text search

Time and Dates

@new_roman11 #javascript

How to Get Current Year in Javascript How to dynamically update your site's copyright year Display Date Objects in Shorter Format - MMM DD YYY HH:MM

JS Methods for Numbers

@goblindoom95 #javascript

toString() - Convert numbers to string toExponential() - Round off numbers in exponential notation toFixed() Method - convert number to string with fixed number of decimal places The valueOf() Method - Returns number of mathematical expression or number variable parseInt() Method - returns a whole number from a string

Dealing with JSON

@mishka #javascript

Creating a JSON Object in Javascript JSON.stringify() - convert objects into JSON JSON.parse() - convert string into a JavaScript object

Gurukula

@noobj #javascript

eventloop_async_blocking.js eventloop_unblocking_event_loop.js macro_and_micro_tasks.js macro_and_micro_tasks.js racer.js process.tick over setImmediate process.tick starving others Good fellow setImmediate setTimeout issue setTimeout issue Non Pure function Pure function mutating function side affects non mutating function, no side affects Immutable examples Immutable examples Immutable examples Higher order functions Higher order functions Higher order functions Higher order functions Higher order functions Test pure functions composition example Pure function Non Pure function composition example Event Loop