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
Agree with you
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
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.
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.
re-rendering could also be caused by react context, it can skip your parent and directly re-render some child