I want to persist some parts of my state tree to the localStorage. What is the appropriate place to do so? Reducer or action? Answer Reducer is never an appropriate place to do this because reducers should be pure and have no side effects. I would recommend just doing it in a subscriber: Before creating the s…
Tag: javascript
Node + Passport, Error: Authentication strategies must have a name
I’m trying to initialize a SAML strategy during the require line. Something like this: but am getting the error: or TypeError: Cannot read property ‘name’ of undefined at Authenticator.use if a custom strategy name is not defined: passport.use(myStrat); . I’ve had it like this (which w…
Ignore clicks in the Chrome Dev Tools pane
I’m trying to look at and alter the style of some elements that display on click and hide when anywhere else on the page is clicked (it’s a modal popup). The problem is that clicking on the developer tools pane triggers the “click anywhere else” action, so the elements I’m trying…
Convert number to “boolean bit array” in JavaScript
I have a number 5. How to get a “boolean bit array” like the array below? array = [false, false, true, false, true]; // 00101 (Need reserve the first two false) Answer This will do:
Getting the angle from a direction vector?
I have this simple function to set an angle for a vector. It effectively gets the vector’s current magnitude (length), calulates the angle and converts the angle from radians to degrees. Then I apply the angle to X and Y, lastly multiplying the vector by it’s original magnitude. However I am unsur…
Angular: conditional class with *ngClass
What is wrong with my Angular code? I am getting the following error: Cannot read property ‘remove’ of undefined at BrowserDomAdapter.removeClass Answer Angular version 2+ provides several ways to add classes conditionally: type one type two and multiple option: type three type four You can find t…
Add array of elements to dom
I have 5 div’s created in HTML, and I want to add all of them into a div wrapper I created in JavaScript. I tried looping through the 5 div’s via a for-in loop, then append the div as a child of the wrapper. For some reason, the for loop changes the 5 div’s order and doesn’t append all…
Move (drag/pan) and zoom object (image or div) in pure js
I’m working on a little script that makes an object (div or img) moveable and zoomable within a given frame. However I came across a few problems I’m not really sure of, because I’m a javascript beginner – so explanation of why those problems occure would be appreciated. Problems: Call…
Calling setState in a loop only updates state 1 time
Is there a reason that calling setSate() in a loop would prevent it from updating the state multiple times? I have a very basic jsbin that highlights the problem I am seeing. There are two buttons. One updates the state’s counter by 1. The other calls the underlying function of One in a loop — whi…
Bootstrap navbar dropdown table without dropdown
How do you create the bootstrap dropdown without the actual button? I want to use this feature somewhere else. Without bootstrap (from http://www.w3schools.com/tags/tag_select.asp): I want what you get when you click on the button, but not the button. Bootstrap styling would be a plus. image from: http://www.…