my array:
var arr= ["1", "2", "3","4","5", "6", "7","8","9","10","11"];
i want to .slice() it so output will be:
var finalArr = [ "1", "2", "4", "5", "6","9","10","11"];
i used sliced like that, but how can i .slice() second element from my array?
var b = [].concat(arr.slice(0, 6), arr.slice(-3)); // output: ["1", "2", "3", "4", "5", "6", "9", "10", "11"]
i know about .splice() but that solution doesn't work for my project
You can use ES6 spread operator:
const result = [arr[0], ...arr.slice(2)];
Or you can even use Array.prototype.filter like so, but be careful of performance if you have big source array:
const result = arr.filter((_, index) => index !== 1);
It's a matter of the right 'end' value in the slicing I suppose.
const initial = ["1", "2", "3","4", "5", "6", "7", "8", "9", "10", "11"];
const finalArr = [ "1", "2", "4", "5", "6", "9", "10", "11"];
// concat the slices
const concatted = initial.slice(0, 2)
.concat(initial.slice(3, 6))
.concat(initial.slice(-3));
// or use the spread operator ...
const spreaded = [
...initial.slice(0, 2),
...initial.slice(3, 6),
...initial.slice(-3) ];
// or flat three sliced subarrays
const flattened = [
initial.slice(0, 2),
initial.slice(3, 6),
initial.slice(-3) ].flat();
// or filter all values NOT in finalArr
const notInFinalArray = initial.filter(v => !finalArr.find(fa => fa === v));
const filtered = initial.filter( v => !notInFinalArray.includes(v) );
console.log(`concatted ${JSON.stringify(concatted)} equals finalArr? ${
JSON.stringify(concatted) === JSON.stringify(finalArr)}`);
console.log(`spreaded ${JSON.stringify(spreaded)} equals finalArr? ${
JSON.stringify(spreaded) === JSON.stringify(finalArr)}`);
console.log(`flattened ${JSON.stringify(flattened)} equals finalArr? ${
JSON.stringify(flattened) === JSON.stringify(finalArr)}`);
console.log(`filtered ${JSON.stringify(filtered)} equals finalArr? ${
JSON.stringify(filtered) === JSON.stringify(finalArr)}`);On your case you can use "push" instead of concat, is more performant:
const arr = ["1", "2", "3","4", "5", "6", "7", "8", "9", "10", "11"];
// concat the slices
var finalArr = arr.slice(0, 2);
finalArr.push(...arr.slice(3, 6),...arr.slice(-3));
console.log(`${JSON.stringify(finalArr)}`);