Spread syntax was introduced as part of Javascript in the ES2015/ECMAS-6.
This allows iterable likes array, object or string to get expanded.
Spread can be used in following ways:
in array : [...iterableArray, 3 , 'four', 5]
in object : {...iterableObj}
The spread operator is very useful for concat, copying,apply, expanding, math operations,etc in array and objects. Let discuss each in detail.
Concat
var arr1 = [1,2,3];
var arr2 = [4,5,6];
without spread
var concatenatedArray = arr1.concat(arr2); // [1,2,3,4,5,6]
with spread
var concatenatedArray = [...arr1, ...arr2 ] // [1,2,3,4,5,6]
Copying
var arr1 = [1,2,3];
var arr2 = [...arr1];
arr2.push(4);
console.log(arr2); // [1,2,3,4]
console.log(arr1); // [1,2,3]
Replacement for apply
var add = (a,b,c) => a+b+c;
var arr1 = [1,2,3];
add(...arr1); // replacing add.apply(null,arr1);
Expanding array
var programming = ["Java", "NodeJs", "Python"];
var subjects = ["Physics", ...programmi…
This allows iterable likes array, object or string to get expanded.
Spread can be used in following ways:
in array : [...iterableArray, 3 , 'four', 5]
in object : {...iterableObj}
The spread operator is very useful for concat, copying,apply, expanding, math operations,etc in array and objects. Let discuss each in detail.
Concat
var arr1 = [1,2,3];
var arr2 = [4,5,6];
without spread
var concatenatedArray = arr1.concat(arr2); // [1,2,3,4,5,6]
with spread
var concatenatedArray = [...arr1, ...arr2 ] // [1,2,3,4,5,6]
Copying
var arr1 = [1,2,3];
var arr2 = [...arr1];
arr2.push(4);
console.log(arr2); // [1,2,3,4]
console.log(arr1); // [1,2,3]
Replacement for apply
var add = (a,b,c) => a+b+c;
var arr1 = [1,2,3];
add(...arr1); // replacing add.apply(null,arr1);
Expanding array
var programming = ["Java", "NodeJs", "Python"];
var subjects = ["Physics", ...programmi…