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Hey, author here :) I am curious about your experiences using/learning React. Are there any other JavaScript topics which are important when starting out with React? Would be great hearing your opinion!
1. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
This article has a lot to offer a JS + React beginner so it feels lame to reply to some tiny part of it, but this bit is a constant error propogated in the ecosystem: > Even though it is possible to mutate the inner properties of objects and arrays when using const, the variable declaration shows the intent of keeping the variable immutable though. let and const only control mutability of the reference. They say noth…
Mutability doesn't need to come into it.
Hey, author here :) I am curious about your experiences using/learning React. Are there any other JavaScript topics which are important when starting out with React? Would be great hearing your opinion!
two minor things that you might include are
1: rest in the context of function args
2: short circuiting: e.g. `isLoading && `
Hey, author here :) I am curious about your experiences using/learning React. Are there any other JavaScript topics which are important when starting out with React? Would be great hearing your opinion!
I wrote a tutorial that would be the next step to yours, called React From Zero[0] I try to teach React here with the basic JavaScript knowledge most people already have.
This article has a lot to offer a JS + React beginner so it feels lame to reply to some tiny part of it, but this bit is a constant error propogated in the ecosystem: > Even though it is possible to mutate the inner properties of objects and arrays when using const, the variable declaration shows the intent of keeping the variable immutable though. let and const only control mutability of the reference. They say noth…
'const prevents reassignment' is a much simpler way of saying that. Mutability doesn't need to come into it.
Hey, author here :) I am curious about your experiences using/learning React. Are there any other JavaScript topics which are important when starting out with React? Would be great hearing your opinion!
One suggestion I'd make is to use ES6 template literals over concatenation, since you're using other ES6 constructs anyway.
getName() {
return `${this.firstname} ${this.lastname}`;
}
I also noticed a lot of people interpreting `const` as "you can not change this, ever". It is short for constant, after all.
Hey, author here :) I am curious about your experiences using/learning React. Are there any other JavaScript topics which are important when starting out with React? Would be great hearing your opinion!
If you are trying to unit test a function that calls another function in the same class you cannot mock the second one it if it is a fat arrow.
Earlier quoted context omitted.
Author here {: Yes, what you are saying here is what I meant. I didn't want to mix in the whole topic around "passing by value or reference" in this short teaser. Hi Swizec :wave: :)
Hi, Robin. Then you may want to say that `const` guarantees that the name will remain bound to that object. The great-GP is correct in that `const` has nothing to do with immutability besides that. It doesn't necessarily conveys an intent of inner immutability. It just states that whatever is in the variable will stay there until it goes out of scope. Using `const` whenever possible is good advice, off course.
Earlier quoted context omitted.
'const prevents reassignment' is a much simpler way of saying that. Mutability doesn't need to come into it.
I agree with you, but I’ve cleared up this confusion with a number of colleagues. People coming from languages that have a truly immutable “const” find the keyword confusing in js.
If someone knows java though, it can always be explained that const in JS is identical to marking a local variable as final in Java.
More so than const, I was perplexed by the JS choice of the `let` keyword. Are there any other languages that use let for declarations that can be reassigned? Did BASIC allow lets to be reassigned? Can’t remember...