Arrayslice 与 Arraysplice：消除混淆

returns the deleted elements in a form of array = array.prototype.slice(startindex, endindex-1);

returns the deleted elements in a form of array = array.prototype.splice(startindex, endindex-1); // permanent 

array.splice(startindex, 0, item1, item2, ..., itemx);

const arr = array.from(array(10), (_, i) => i+1);
console.log('array --> ', arr);
console.log('get a new array that includes numbers from 4 to 8 --> ', arr.slice(3, 8)); // array.prototype.slice(startindex, endindex-1);

// [ 4, 5, 6, 7, 8 ]

const fruits = ['apple', 'banana', 'orange', 'mango', 'kiwi'];

fruits.splice(0, 2)// permanent

console.log('splice method to remove "apple" and "banana" from the array. --> ', fruits);

// [ 'orange', 'mango', 'kiwi' ]

const colors = ['red', 'green', 'blue'];

const y = colors.splice(1, 0, "pink", "purple"); /
console.log(y); // [] see above to see why.
console.log('splice method to add "pink" and "purple" after "red" --> ', colors)

// [ 'red', 'pink', 'purple', 'green', 'blue' ]

const letters = ['a', 'b', 'c', 'd', 'e'];
const newSlice = letters.slice(0, 3);
const x = letters.splice(0, 3);
console.log(x);
console.log('slice to get a new array of the first three letters --> ', newSlice) // [ 'a', 'b', 'c' ]

console.log('Then use splice on the original array to remove these letters --> ', letters)[ 'd', 'e' ]