Typescript - Kotlin-like copy function
0
In Kotlin a data class can be copied using its auto-generated copy function.
val jack = User(name = "Jack", age = 1)
val olderJack = jack.copy(age = 2)
The copy function signature, as per documentation (Docs):
fun copy(name: String = this.name, age: Int = this.age) = User(name, age)
Can something like this be done in TypeScript?
Is this an acceptable solution, or can it be improved somehow?
export class User {
constructor(
public name: string,
public age: number) {}
copy(parameters: {
name?: string,
age?: number
}): User {
const { name, age } = parameters
return new User(name || this.name, age || this.age)
}
}
This could be solved even with a Partial<User>:
copy(partialUser: Partial<User>): User {
return new User(
partialUser.name || this.name,
partialUser.age || this.age)
}
typescript
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
add a comment |
0
In Kotlin a data class can be copied using its auto-generated copy function.
val jack = User(name = "Jack", age = 1)
val olderJack = jack.copy(age = 2)
The copy function signature, as per documentation (Docs):
fun copy(name: String = this.name, age: Int = this.age) = User(name, age)
Can something like this be done in TypeScript?
Is this an acceptable solution, or can it be improved somehow?
export class User {
constructor(
public name: string,
public age: number) {}
copy(parameters: {
name?: string,
age?: number
}): User {
const { name, age } = parameters
return new User(name || this.name, age || this.age)
}
}
This could be solved even with a Partial<User>:
copy(partialUser: Partial<User>): User {
return new User(
partialUser.name || this.name,
partialUser.age || this.age)
}
typescript
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
add a comment |
0
0
0
1
In Kotlin a data class can be copied using its auto-generated copy function.
val jack = User(name = "Jack", age = 1)
val olderJack = jack.copy(age = 2)
The copy function signature, as per documentation (Docs):
fun copy(name: String = this.name, age: Int = this.age) = User(name, age)
Can something like this be done in TypeScript?
Is this an acceptable solution, or can it be improved somehow?
export class User {
constructor(
public name: string,
public age: number) {}
copy(parameters: {
name?: string,
age?: number
}): User {
const { name, age } = parameters
return new User(name || this.name, age || this.age)
}
}
This could be solved even with a Partial<User>:
copy(partialUser: Partial<User>): User {
return new User(
partialUser.name || this.name,
partialUser.age || this.age)
}
typescript
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
In Kotlin a data class can be copied using its auto-generated copy function.
val jack = User(name = "Jack", age = 1)
val olderJack = jack.copy(age = 2)
The copy function signature, as per documentation (Docs):
fun copy(name: String = this.name, age: Int = this.age) = User(name, age)
Can something like this be done in TypeScript?
Is this an acceptable solution, or can it be improved somehow?
export class User {
constructor(
public name: string,
public age: number) {}
copy(parameters: {
name?: string,
age?: number
}): User {
const { name, age } = parameters
return new User(name || this.name, age || this.age)
}
}
This could be solved even with a Partial<User>:
copy(partialUser: Partial<User>): User {
return new User(
partialUser.name || this.name,
partialUser.age || this.age)
}
typescript
typescript
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
edited Nov 26 '18 at 11:40
LppEdd
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
asked Nov 26 '18 at 11:02
LppEddLppEdd
9,40621647
9,40621647
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
2
You can deconstruct the item as shown below:
class User {
constructor(
public name: string,
public age: number) {}
}
const jack = new User("Jack", 1);
const newJack = { ...jack, age: 2 };
This results in the copy, except the age, which is now 2.
The ordering is important (i.e. age must follow the object deconstruction).
Extended example below:
class User {
constructor(
public name: string,
public age: number) { }
copy(user: Pick<User, 'name' | 'age'>) {
return new User(user.name, user.age);
}
}
const jack = new User("Jack", 1);
const newJack = jack.copy({ ...jack, age: 2 });
console.log(newJack);
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
Wouldn't I lose eventual instance / static functions?
– LppEdd
Nov 26 '18 at 11:34
I have added a wider example wherenewJackis the fullUser.
– Fenton
Nov 26 '18 at 11:38
Thanks! Do you findPickmore appropriate thenPartial?
– LppEdd
Nov 26 '18 at 11:39
WithPickyou say "it must have the members I state", wherasPartialsays "I don't know what it's going to have". In our case, we can be quite strict that we expect name and age to be supplied and we don't care aboutcopy. So the following will be caught as an error in ourPickexample:const newJack = jack.copy({ age: 2 });
– Fenton
Nov 26 '18 at 11:40
Interesting! I could even just use(user: Pick<User>): User { ... }then. Do you think that myPartialexample was not appropriate? I ask so I'm able to understand if I'm doing right or wrong in general terms
– LppEdd
Nov 26 '18 at 11:44
|
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
2
You can deconstruct the item as shown below:
class User {
constructor(
public name: string,
public age: number) {}
}
const jack = new User("Jack", 1);
const newJack = { ...jack, age: 2 };
This results in the copy, except the age, which is now 2.
The ordering is important (i.e. age must follow the object deconstruction).
Extended example below:
class User {
constructor(
public name: string,
public age: number) { }
copy(user: Pick<User, 'name' | 'age'>) {
return new User(user.name, user.age);
}
}
const jack = new User("Jack", 1);
const newJack = jack.copy({ ...jack, age: 2 });
console.log(newJack);
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
Wouldn't I lose eventual instance / static functions?
– LppEdd
Nov 26 '18 at 11:34
I have added a wider example wherenewJackis the fullUser.
– Fenton
Nov 26 '18 at 11:38
Thanks! Do you findPickmore appropriate thenPartial?
– LppEdd
Nov 26 '18 at 11:39
WithPickyou say "it must have the members I state", wherasPartialsays "I don't know what it's going to have". In our case, we can be quite strict that we expect name and age to be supplied and we don't care aboutcopy. So the following will be caught as an error in ourPickexample:const newJack = jack.copy({ age: 2 });
– Fenton
Nov 26 '18 at 11:40
Interesting! I could even just use(user: Pick<User>): User { ... }then. Do you think that myPartialexample was not appropriate? I ask so I'm able to understand if I'm doing right or wrong in general terms
– LppEdd
Nov 26 '18 at 11:44
|
show 2 more comments
2
You can deconstruct the item as shown below:
class User {
constructor(
public name: string,
public age: number) {}
}
const jack = new User("Jack", 1);
const newJack = { ...jack, age: 2 };
This results in the copy, except the age, which is now 2.
The ordering is important (i.e. age must follow the object deconstruction).
Extended example below:
class User {
constructor(
public name: string,
public age: number) { }
copy(user: Pick<User, 'name' | 'age'>) {
return new User(user.name, user.age);
}
}
const jack = new User("Jack", 1);
const newJack = jack.copy({ ...jack, age: 2 });
console.log(newJack);
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
Wouldn't I lose eventual instance / static functions?
– LppEdd
Nov 26 '18 at 11:34
I have added a wider example wherenewJackis the fullUser.
– Fenton
Nov 26 '18 at 11:38
Thanks! Do you findPickmore appropriate thenPartial?
– LppEdd
Nov 26 '18 at 11:39
WithPickyou say "it must have the members I state", wherasPartialsays "I don't know what it's going to have". In our case, we can be quite strict that we expect name and age to be supplied and we don't care aboutcopy. So the following will be caught as an error in ourPickexample:const newJack = jack.copy({ age: 2 });
– Fenton
Nov 26 '18 at 11:40
Interesting! I could even just use(user: Pick<User>): User { ... }then. Do you think that myPartialexample was not appropriate? I ask so I'm able to understand if I'm doing right or wrong in general terms
– LppEdd
Nov 26 '18 at 11:44
|
show 2 more comments
2
2
2
You can deconstruct the item as shown below:
class User {
constructor(
public name: string,
public age: number) {}
}
const jack = new User("Jack", 1);
const newJack = { ...jack, age: 2 };
This results in the copy, except the age, which is now 2.
The ordering is important (i.e. age must follow the object deconstruction).
Extended example below:
class User {
constructor(
public name: string,
public age: number) { }
copy(user: Pick<User, 'name' | 'age'>) {
return new User(user.name, user.age);
}
}
const jack = new User("Jack", 1);
const newJack = jack.copy({ ...jack, age: 2 });
console.log(newJack);
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
You can deconstruct the item as shown below:
class User {
constructor(
public name: string,
public age: number) {}
}
const jack = new User("Jack", 1);
const newJack = { ...jack, age: 2 };
This results in the copy, except the age, which is now 2.
The ordering is important (i.e. age must follow the object deconstruction).
Extended example below:
class User {
constructor(
public name: string,
public age: number) { }
copy(user: Pick<User, 'name' | 'age'>) {
return new User(user.name, user.age);
}
}
const jack = new User("Jack", 1);
const newJack = jack.copy({ ...jack, age: 2 });
console.log(newJack);
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
edited Nov 26 '18 at 11:37
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
answered Nov 26 '18 at 11:33
FentonFenton
157k46294318
157k46294318
Wouldn't I lose eventual instance / static functions?
– LppEdd
Nov 26 '18 at 11:34
I have added a wider example wherenewJackis the fullUser.
– Fenton
Nov 26 '18 at 11:38
Thanks! Do you findPickmore appropriate thenPartial?
– LppEdd
Nov 26 '18 at 11:39
WithPickyou say "it must have the members I state", wherasPartialsays "I don't know what it's going to have". In our case, we can be quite strict that we expect name and age to be supplied and we don't care aboutcopy. So the following will be caught as an error in ourPickexample:const newJack = jack.copy({ age: 2 });
– Fenton
Nov 26 '18 at 11:40
Interesting! I could even just use(user: Pick<User>): User { ... }then. Do you think that myPartialexample was not appropriate? I ask so I'm able to understand if I'm doing right or wrong in general terms
– LppEdd
Nov 26 '18 at 11:44
|
show 2 more comments
Wouldn't I lose eventual instance / static functions?
– LppEdd
Nov 26 '18 at 11:34
I have added a wider example wherenewJackis the fullUser.
– Fenton
Nov 26 '18 at 11:38
Thanks! Do you findPickmore appropriate thenPartial?
– LppEdd
Nov 26 '18 at 11:39
WithPickyou say "it must have the members I state", wherasPartialsays "I don't know what it's going to have". In our case, we can be quite strict that we expect name and age to be supplied and we don't care aboutcopy. So the following will be caught as an error in ourPickexample:const newJack = jack.copy({ age: 2 });
– Fenton
Nov 26 '18 at 11:40
Interesting! I could even just use(user: Pick<User>): User { ... }then. Do you think that myPartialexample was not appropriate? I ask so I'm able to understand if I'm doing right or wrong in general terms
– LppEdd
Nov 26 '18 at 11:44
Wouldn't I lose eventual instance / static functions?
– LppEdd
Nov 26 '18 at 11:34
Wouldn't I lose eventual instance / static functions?
– LppEdd
Nov 26 '18 at 11:34
I have added a wider example where
newJack is the full User.– Fenton
Nov 26 '18 at 11:38
I have added a wider example where
newJack is the full User.– Fenton
Nov 26 '18 at 11:38
Thanks! Do you find
Pick more appropriate then Partial?– LppEdd
Nov 26 '18 at 11:39
Thanks! Do you find
Pick more appropriate then Partial?– LppEdd
Nov 26 '18 at 11:39
With
Pick you say "it must have the members I state", wheras Partial says "I don't know what it's going to have". In our case, we can be quite strict that we expect name and age to be supplied and we don't care about copy. So the following will be caught as an error in our Pick example: const newJack = jack.copy({ age: 2 });– Fenton
Nov 26 '18 at 11:40
With
Pick you say "it must have the members I state", wheras Partial says "I don't know what it's going to have". In our case, we can be quite strict that we expect name and age to be supplied and we don't care about copy. So the following will be caught as an error in our Pick example: const newJack = jack.copy({ age: 2 });– Fenton
Nov 26 '18 at 11:40
Interesting! I could even just use
(user: Pick<User>): User { ... } then. Do you think that my Partial example was not appropriate? I ask so I'm able to understand if I'm doing right or wrong in general terms– LppEdd
Nov 26 '18 at 11:44
Interesting! I could even just use
(user: Pick<User>): User { ... } then. Do you think that my Partial example was not appropriate? I ask so I'm able to understand if I'm doing right or wrong in general terms– LppEdd
Nov 26 '18 at 11:44
|
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