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Feb 1

Matlab Basics— How to access array elements based on their position (index) in the array

Indexing with Element Positions e is the element in the 3,2 position (third row, second column) of A. You can also reference multiple elements at a time by specifying their indices in a vector. For example, access the first and third elements of the second row of A.

Matlab

2 min read

Matlab Basics— How to access array elements based on their position (index) in the array
Matlab Basics— How to access array elements based on their position (index) in the array
Matlab

2 min read


Nov 29, 2022

React.js — How to manually trigger onChange event?

Code: var event = new MouseEvent('click', { 'view': window, 'bubbles': true, 'cancelable': false }); var node = document.getElementById('nodeMyComponentsEventIsConnectedTo'); node.dispatchEvent(event);

JavaScript

1 min read

JavaScript

1 min read


Nov 17, 2022

JavaScript — How to create and fill an empty array with a given size?

Solution const arr = Array(5).fill(""); console.log(arr); //prints out ["","","","",""] console.log(arr[0]); //prints out "" 1) To create new array which, you cannot iterate over, you can use array constructor: Array(100) or new Array(100) 2) You can create new array, which can be iterated over like below: a) All JavaScript versions Array.apply: Array.apply(null…

JavaScript

1 min read

JavaScript

1 min read


Nov 10, 2022

How to ensure an event listener is only fired once in JavaScript

1. Using the once option We can pass an object as an argument to the addEventListener method and specify that the event is only handled once. This is achieved by passing the property once to the object. If we set once to true, the event will only be fired once. let btn = document.getElementById('btn'); btn.addEventListener("click", function()…

JavaScript

1 min read

JavaScript

1 min read


Nov 2, 2022

JavaScript — How to place a div side by side

Here are 2 ways to place a div side by side. Using CSS float property: <div style="width: 100%; overflow: hidden;"> <div style="width: 600px; float: left;"> Left </div> <div style="margin-left: 620px;"> Right </div> </div> 2. Using CSS display property - which can be used to make divs act like a table: …

HTML

1 min read

HTML

1 min read


Nov 1, 2022

How to prettify a JSON object on the browser

To prettify a JSON object on the browser, use the <pre> tag. var data = { "data": { "x": "1", "y": "1", "url": "http://url.com" }, "event": "start", "show": 1, "id": 50 } document.getElementById("json").textContent = JSON.stringify(data, undefined, 2); <pre id="json"></pre> pre tells the browser engine that the content inside is pre-formatted and it can be displayed without any modification. So browser will not…

JavaScript

1 min read

JavaScript

1 min read


Oct 31, 2022

Solution to ‘Missing write access to /usr/local/lib/node_modules’ error

What to do when you have this output on the terminal when you try to download a node package with NPM? npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules npm ERR! path /usr/local/lib/node_modules npm ERR! code EACCES npm ERR! errno -13 npm ERR! syscall access npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules' npm ERR! { [Error: EACCES: permission denied, access '/usr/local/lib/node_modules'] npm ERR! stack: npm ERR! 'Error: EACCES: permission denied, access \'/usr/local/lib/node_modules\'', npm…

JavaScript

1 min read

JavaScript

1 min read


Oct 28, 2022

JavaScript — How to add an eventListener to multiple elements

Method #1: Use a for loop through all input elements let elementsArray = document.querySelectorAll("input"); elementsArray.forEach(function(elem) { elem.addEventListener("input", function() { console.log("CHANGE!"); }); }); Method #2: Listen to the ‘document’ document.addEventListener('click', function(e){ if(e.target.tagName=="BUTTON"){ console.log("CHANGE!"); } }) Explanation: Event Bubbling is the important concept in javascript, so if you can add event on DOM directly, you can save some lines of code, no need for looping.

JavaScript

1 min read

JavaScript

1 min read


Oct 27, 2022

JavaScript — 3 ways to combine an array and remove its duplicates

Method #1: for loop let array1 = ['a','b','c'] let array2 = ['c','c','d','e']; let array3 = []; for(let i=0;i<array1.length;i++){ if(array3.indexOf(array1[i]) == -1) array3.push(array1[i]) } for(let i=0;i<array2.length;i++){ if(array3.indexOf(array2[i]) == -1) array3.push(array2[i]) } return array3; Overall time complexity: Big O(n²) Method #2: using concat and filter (ES5 solution) let array1 = ['a','b','c']

JavaScript

1 min read

JavaScript

1 min read


Oct 26, 2022

JavaScript — Comparison between ‘for loop’ vs. ‘forEach’

for loop for loops are much more efficient. It is a looping construct specifically designed to iterate while a condition is true, at the same time offering a stepping mechanism (generally to increase the iterator). Example: for (var i=0, n=arr.length; i < n; ++i ) { ... } This isn’t to suggest…

JavaScript

3 min read

JavaScript

3 min read

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