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How to safe get value from object (return null when not exist)

I want to lookup for a key on an object, but if the key does’t exist, it must return null, is it possible in JavaScript? Answer You can use or: || or the newer optional chaining and Nullish coalescing operator NOTE: the arrow function suggested by Máté Wiszt has to be wrapped in () or it will give an er…

Javascript Dynamic Data binding code not working

I am writing code that uses data binding to change the innerHTML of an span to the input of the user, but I can’t get it to work. What it should do is show the input on the right side of the input field on both the input fields, but it doesn’t. Can someone please help me out. HTML: Javascript:

JavaScript sort multiple array

Suppose I have this data Name Mark John 76 Jack 55 Dani 90 and for the grade Marks Grade 100-80 A 79 – 60 B 59 – 40 C suppose i declare the script as The program should assign the grade with the corresponding mark, how do I sort the grade since we know we cant change the index for

Increment 2 variables in paralell Node-RED

I am trying to create a script that creates 2 variables, and increments each one of them based on a condition. The actualNetWeight is received in real-time with a MQTT connection to a server and the values are displayed in a line chart. When this value is over or equals to 0.500, I have to count that item ent…

React.js, map is not rendering components

I have this as top component: This is my Main component: And this is Thread component: But iteration is never reaching Thread component. And this [{ post: “b” }] that i used as initial state is not getting printed on screen. What could be the issue? That is currently the output coming: Answer It i…