inplace-copy

Description

inplace-copy deeply copy object to object in-place. In-place copying, so it does not break data references. Therefore, if the data content is the same, reactive data triggers by vue watch, computed, etc. will not fire.

Following features,

• Deep copy object to object
• Customize how to copy array content
• Instance-specific copying methods (eg: Date)

Install

npm install inplace-copy

Usage

const copy = deepCopy()
const xs = {a: {b: 1}}
const ys = {a: {b: 2}, c: 3}
const zs = copy(xs, ys)
// typeof zs is now same as ys
console.log(zs) // {a: {b: 2}, c: 3}
console.log(Object.is(zs, xs)) // true
console.log(Object.is(zs.b, xs.b)) // true

Options

keyOfObject

Arrays are copied by default based on position.

const copy = deepCopy()
const xs = [{a: 1}]
const ys = [{b: 2}]
const zs = copy(xs, ys)
console.log(zs) // [{b: 2}]

For arrays, it is not a good practice to rely only on the position of the values inside to copy.

Therefore, we can specify a method to check if the objects in the array are identical.

const keyOfObject = (v: any, i: index) => v.id
const copy = deepCopy({ keyOfObject })
const bob = {id: 'bob', age: 20}
const xs = [bob]
const ys = [{id: 'mary', age: 19}, {id: 'bob', age: 21}]
const zs = copy(xs, ys)
console.log(zs) // [{id: 'mary', age: 19}, {id: 'bob', age: 21}]
console.log(Object.is(zs, xs)) // true
console.log(Object.is(zs[1], bob)) // true

copyMethods

You can customize how objects are copied by specifying a two-element tuple consisting of a function to determine the runtime type and the copy method.

This is useful for built-in Date types and user-defined type copying, including functions.

const isDate = (v: Date): v is Date => v instanceof Date
const copyDate = (target: any, source: Date, next: any) => {
  target.setTime(source.getTime())
  return target
}
const copy = deepCopy({ copyMethods: [[isDate, copyDate]] })

const xst =  new Date('1995-12-17T03:24:00')
const xs = {a: xst}
const yst =  new Date('1995-12-17T03:24:00')
const ys = {a: yst}

const copy = deepCopy({ copyMethods: [[isDate, copyDate]] })
const zs = copy(xs, ys)
console.log(zs.a, xst) // true, xst is modified

Licence

MIT

Author

iridge-mu