将数组中的对象拼接到新数组中

Question

I have two arrays of objects which I would like to combine into a new array, splicing each object from one array into another based on the previewNumber value as the index used in .splice . I've used .map but it only loops for the length of arrayOne , below is some example code, any help would be greatly appreciated

 const arrayOne = [ { "title": "A Project", "slug": "a-project", "previewNumber": 2, }, { "title": "New Project", "slug": "new-project", "previewNumber": 4, } ] const arrayTwo = [ { "title": "Project 5546", "slug": "project-5546", }, { "title": "Project 456", "slug": "project-456", }, { "title": "Rand Project 467", "slug": "rand-project-467", }, { "title": "Random Project 245", "slug": "random-project-245", }, { "title": "Example Project", "slug": "example-project", }, ] const newArray = arrayOne.map((item) => arrayTwo.splice(item.previewNumber, 0, item) ); console.log(newArray) const desiredOutput = [ { "title": "Project 5546", "slug": "project-5546", }, { "title": "Project 456", "slug": "project-456", }, { "title": "A Project", "slug": "a-project", "previewNumber": 2, }, { "title": "Rand Project 467", "slug": "rand-project-467", }, { "title": "Random Project 245", "slug": "random-project-245", }, { "title": "New Project", "slug": "new-project", "previewNumber": 4, }, { "title": "Example Project", "slug": "example-project", }, ]

Answer 1

You can achieve this using flatMap . Here is an implementattion.

 const arrayOne = [ { "title": "A Project", "slug": "a-project", "previewNumber": 2, }, { "title": "New Project", "slug": "new-project", "previewNumber": 4, }]; const arrayTwo = [ { "title": "Project 5546", "slug": "project-5546", }, { "title": "Project 456", "slug": "project-456", }, { "title": "Rand Project 467", "slug": "rand-project-467", }, { "title": "Random Project 245", "slug": "random-project-245", }, { "title": "Example Project", "slug": "example-project", }]; const result = arrayTwo.flatMap((p,i)=>{ position = arrayOne.find(k=>k.previewNumber===i); return position ? [position, p] : p }); console.log(result);

Or you can convert the arrayOne to objects. Something like this:

 const arrayOne = [ { "title": "A Project", "slug": "a-project", "previewNumber": 2, }, { "title": "New Project", "slug": "new-project", "previewNumber": 4, }]; const mapped = Object.fromEntries(arrayOne.map(p=>[p.previewNumber,p])); const arrayTwo = [ { "title": "Project 5546", "slug": "project-5546", }, { "title": "Project 456", "slug": "project-456", }, { "title": "Rand Project 467", "slug": "rand-project-467", }, { "title": "Random Project 245", "slug": "random-project-245", }, { "title": "Example Project", "slug": "example-project", }]; const result = arrayTwo.flatMap((p,i)=>mapped[i] ? [mapped[i], p] : p); console.log(result);

Answer 2

First, make the newArray copy of arrayTwo . After that, you could iterate through arrayOne add into newArray by splicing from previewNumber + index

const newArray = [...arrayTwo]
arrayOne.forEach((el, index) => {
  newArray.splice(el.previewNumber + index, 0, el)
})

console.log(newArray)

Full demo

 const arrayOne = [ { title: "A Project", slug: "a-project", previewNumber: 2, }, { title: "New Project", slug: "new-project", previewNumber: 4, }, ] const arrayTwo = [ { title: "Project 5546", slug: "project-5546", }, { title: "Project 456", slug: "project-456", }, { title: "Rand Project 467", slug: "rand-project-467", }, { title: "Random Project 245", slug: "random-project-245", }, { title: "Example Project", slug: "example-project", }, ] const newArray = [...arrayTwo] arrayOne.forEach((el, index) => { newArray.splice(el.previewNumber + index, 0, el) }) console.log(newArray)