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export class Immutable<S> { | |
private obj: S; | |
constructor(obj: S) { | |
Object.freeze(obj); | |
if (typeof obj === 'object') { | |
Object.keys(obj).forEach((key: string): void => { | |
Object.freeze(obj[key]); | |
}); | |
} | |
this.obj = obj; | |
} | |
get v(): S { | |
return this.obj; | |
} | |
set(f: (objCopy: S) => S): Immutable<S> { | |
let objCopy: S; | |
if (Array.isArray(this.obj)) { | |
objCopy = (<any>this.obj).slice(); | |
} else if (typeof this.obj === 'object') { | |
objCopy = Object.assign({}, this.obj); | |
} else { | |
objCopy = this.obj; | |
} | |
return new Immutable(f(objCopy)); | |
} | |
} |
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import {Immutable} from './immutable'; | |
import {Person} from './simple'; | |
type GangMember = Immutable<Person>; | |
interface Gang { | |
sign: string; | |
assets: string[]; | |
members: Immutable<GangMember[]>; | |
} | |
let gang: Immutable<Gang>; | |
let member1 = new Immutable({ name: 'John', height: 1337 }); | |
let member2 = new Immutable({ name: 'Doe', height: 42 })'' | |
gang = new Immutable<Gang>({ | |
sign: 'frontend', | |
assets: ['tags'], | |
members: new Immutable([ | |
member1, | |
member2 | |
]), | |
}); | |
let homer = new Immutable({ name: 'Homer', height: 110 }); | |
console.log(gang.v.assets.length) // 1 | |
try { | |
gang.v.assets.push('attributes'); | |
} catch (e) { | |
// TypeError: Can't add property "attributes", object is not extensible | |
} | |
console.log(gang.v.assets.length) // 1 | |
console.log(gang.v.members.v.length); // 2 | |
gang = gang.set((gang: Gang): Gang => { | |
gang.members = gang.members.set((members: GangMember[]): GangMember[] => { | |
members.push(homer); | |
return members; | |
}); | |
return gang; | |
}); | |
console.log(gang.v.members.v.length); // 3 | |
console.log(gang.v.members.v[0] === member1); // true | |
console.log(gang.v.members.v[2].v.name); // Homer | |
homer.v.name = 'Bart'; | |
console.log(gang.v.members.v[2].v.name); // Homer | |
gang = gang.set((gang: Gang): Gang => { | |
gang.members = gang.members.set((members: GangMember[]): GangMember[] => { | |
members.push(homer); | |
members[2] = members[2].set((member: Person): Person => { | |
member.name = 'Bart'; | |
return member; | |
}); | |
return members; | |
}); | |
return gang; | |
}); | |
console.log(gang.v.members.v[2].v.name); // Bart |
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import {Immutable} from './immutable'; | |
export interface Person { | |
name: string; | |
height: number; | |
} | |
let person: Immutable<Person>; | |
person = new Immutable({ | |
name: 'John', | |
height: 1337, | |
}); | |
console.log(person.v.name); // John | |
person.v.name = 'Doe'; | |
console.log(person.v.name); // John | |
person = person.set((person: Person): Person => { | |
person.name = 'Doe'; | |
return person; | |
}); | |
console.log(person.v.name); // Doe |
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