"immutable-record-updater" is the library, which helps you update record without breaking changes.
npm i --save-dev @mm1995tk/immutable-record-updater
suppose you define a type "Person".
type Person = {
name: string;
age: number;
from: {
name: string;
category: string;
famous: {
people: string[];
place: {
park: string[];
};
};
};
living: {
name: string;
category: string;
famous: {
people: string[];
place: {
park: string[];
};
};
};
};
const person: Person = {
name: 'John Smith',
age: 28,
from: {
name: 'New York',
category: 'City',
famous: {
people: ['Jay-Z', 'Lady Gaga'],
place: {
park: ['Central Park', 'Battery Park'],
},
},
},
living: {
name: 'Los Angeles',
category: 'City',
famous: {
people: ['Kobe Bryant', 'LeBron James'],
place: {
park: ['Griffith Park'],
},
},
},
};if you update person.from.famous.people and person.living.famous.place.park without breaking changes by scratch, it will be...
const person2: Person = {
...person,
from: {
...person.from,
famous: {
...person.from.famous,
people: [...person.from.famous.people, 'Beyoncé'],
},
},
living: {
...person.living,
famous: {
...person.living.famous,
place: {
...person.living.famous.place,
park: [...person.living.famous.place.park, 'Echo Park'],
},
},
},
};but you can do same thing more simply by using this library.
import imRecUp from '@mm1995tk/immutable-record-updater';
const updater = imRecUp.generateRecordUpdater<Person>();
const program = updater
.set('from.famous.people', item => [...item, 'Beyoncé'])
.set('living.famous.place.park', item => [...item, 'Echo Park']);
const person2 = program.run(person); // { success: true, data: {..}}If you wish to add restrictions (e.g., age must not be less than 30), you can do it like this.
import imRecUp from '@mm1995tk/immutable-record-updater';
type ErrKind = 'AgeIsLessThanTen';
const updater = imRecUp.generateRecordUpdater<Person, ErrKind>(person => person.age >= 30 || 'AgeIsLessThanTen');
const program = updater
.set('from.famous.people', item => [...item, 'Beyoncé'])
.set('living.famous.place.park', item => [...item, 'Echo Park']);
const person2 = program.run(person); // { success: false, error: ['AgeIsLessThanTen'] data: {..}}Also, if you want to decide how to update from the current state, do it like this.
import imRecUp from '@mm1995tk/immutable-record-updater';
type ErrKind = 'AgeIsLessThanTen';
const updater = imRecUp.generateRecordUpdater<Person, ErrKind>(person => person.age >= 30 || 'AgeIsLessThanTen');
const program = updater
.set('age', (item, getPreState) => {
const preState = getPreState();
// checking if data satisfy constraints
if (preState.success) {
return item;
}
return item + 5;
})
.set('from.famous.people', item => [...item, 'Beyoncé'])
.set('living.famous.place.park', item => [...item, 'Echo Park']);
const person2 = program.run(person); // { success: true, data: {..}}
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