es6 Array immutable Array Actions

Javascript immutable Operations es6Array.md

I have an array by the name students and a student object

let students = []

let student = {
  name: '',
  rollNumber: '',
  age: '',
  rank: ''
}

Following are immutable array Operations

1. adding an element to the array

  students.concat([student])

2. Deleting an object based on index from array

   var newStudentsArray = [...students.slice(0,index), ...students(index + 1)];

3. Deleting an object from the array based on some property

    var newStudentArray = students.filter((student) => student.rank < 5) 
   // will return a new array of all students whose rank is less than 5

###4. Updating a value of a particular object

   var newStudentArray = students.map((student) => {
    if(someProperty !== student.key) return student
    return Object.assign({}, student, NEW_OBJECT)
   })

or in Es6

   var newStudentArray = students.map((student) => {
    if(someProperty !== student.key) return student
    return {...student, NEW_OBJECT}
   })