once upon time...
💎 Generation of class component
🚩 Pure component()
Compare new and old props/state, if there is difference...
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and Object, Array is pass by referenceI dont think it's actually true. In JS, we only have pass-by-value.
Pass-by-referencemeans we will pass the ADDRESS of VARIABLE. But in JS, we pass the object which variable is referring. So it's not pass-by-referenceEverything in JavaScript is pass-by-reference so if your function modifies an object or array then the change applies to the original object.
The case of the "pass-by-value" in primitive date types it's because primitive data types are immutable so yeah, you are still passing the reference to a function but it doesn't matter cause its immutability
Please take a look
stackoverflow.com/questions/131044...
Thanks, exactly what I said but remember primitives are immutable so that why they act as "pass-by-value"
Oh, let me confirm again. In JS, we only "pass-by-value"
Okay, I got your point.
Technically, JS works "pass-by-value" since you pass a copy of a reference. But if you modify that copy of the reference then it modifies the original object so that's basically "pass-by-reference" xd
Same as Primitive Data Types Immutability is basically the same as pass-by-value.
So it depends, you can see the glass half empty or half full
I think there's problem with React.memo example. Change determination function should be like the following instead...
return nextProps.value !== prevProps.valueNot like the following...
return nextProps.value === prevProps.valueBecause it should re-render only when old value not equal to new value
Very informative! Would be nice to have an example for
useCallbacktoo though! It is not very clear to me :/+1 for the example of the useCallback. Would appreciate it.
Amazing explanations, but my small problem is that i quite dont understand when exactly do i need one of this things, i guess i will understand it with time cuz i think there is no universal rule for each website. Thanks for this article.
re-rendering could also be caused by react context, it can skip your parent and directly re-render some child