Add Class type (i.e. a Record but no default values) #839
Comments
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@OliverJAsh is this in TypeScript? Did this comment not work out for you? |
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Yes, it is in TypeScript. Thanks for the link, I'm trying to make sense of it all but a lot of it is going over my head. Seems like it should be simpler? |
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Unfortunately I don't think this is possible, as what you're asking for is syntactic rather than library code. A default value must always exist, because you can always do var MyRecordType = Record({
myField1: undefined,
myField2: undefined
}) |
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We have a slightly nicer syntax coming in a future version that lets you provide coercion functions rather than just default values: |
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@OliverJAsh the immutable aspect you require does not require ImmutableJS. You can use the type checking of TypeScript to achieve the same thing (indeed there is a performance benefit to doing so). Consider: class A1 {
private name: string;
private age: number;
private hobbies: Immutable.Set<string>;
constructor() {
// could set defaults here... or take parameters
// to assign
}
Name(): string {
return this.name;
}
SetName(v: string): A1 {
if(v === this.name) {
return this;
}
let res = this.dup();
res.name = v;
return res;
}
Age(): number {
return this.age;
}
SetAge(v: number): A1 {
if(v === this.age) {
return this;
}
let res = this.dup();
res.age = v;
return res;
}
Hobbies(): Immutable.Set<string> {
return this.hobbies;
}
SetHobbies(v: Immutable.Set<string>): A1 {
if(v === this.hobbies) {
return this;
}
let res = this.dup();
res.hobbies = v;
return res;
}
private dup(): A1 {
let res = new A1();
res.hobbies = this.hobbies;
res.age = this.age;
res.name = this.name;
return res;
}
}
let x1 = new A1();
let x2 = x1.SetName("Paul");
console.log(x1 === x2); // false
console.log(x1.Name()); // undefined
console.log(x2.Name()); // "Paul"Here the model class You will notice the primitive properties ( If you are using the latest class A1 {
private name: string;
private age: number;
private hobbies: Immutable.Set<string>;
constructor() {
// could set defaults here... or take parameters
// to assign
}
get Name(): string { // getter
return this.name;
}
SetName(v: string): A1 {
if(v === this.name) {
return this;
}
let res = this.dup();
res.name = v;
return res;
}
get Age(): number { // getter
return this.age;
}
SetAge(v: number): A1 {
if(v === this.age) {
return this;
}
let res = this.dup();
res.age = v;
return res;
}
get Hobbies(): Immutable.Set<string> { // getter
return this.hobbies;
}
SetHobbies(v: Immutable.Set<string>): A1 {
if(v === this.hobbies) {
return this;
}
let res = this.dup();
res.hobbies = v;
return res;
}
private dup(): A1 {
let res = new A1();
res.hobbies = this.hobbies;
res.age = this.age;
res.name = this.name;
return res;
}
}
let x1 = new A1();
let x2 = x1.SetName("Paul");
console.log(x1 === x2); // false
console.log(x1.Name); // undefined
console.log(x2.Name); // "Paul" |
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@leebyron Is there any reason why |
The constructor could error if not given all the specified parameters. Then if you don't have a |
I want an immutable object with typed properties (TypeScript). I want something like a Record, but without default values.
In Scala we have case classes that do this. Would it be possible to add this type to immutable-js?
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