I would like to know if i can add an element in my array with a specific key with Spread Operator.
let foo = ['a','b','c'];
foo = [...foo,'d'];
In this case foo[3] would be d. But can i add d with a custon key in my foo array and then access with something like: foo['customKey']?
You could take Object.assign instead of spreading an array, because this allows only to take iterable items for the new array.
let foo = ['a','b','c'];
foo = Object.assign([], [...foo], { customKey: 'd' });
console.log(foo);
console.log(foo.customKey);Arrays are objects in JavaScript therefore they can have properties:
let foo = ['a','b','c'];
foo['customKey'] = 'd';
//Note using a for-in not for-of to iterate over enumerable & string properties
for (i in foo){
console.log("The type of index is also a string: ", typeof i, i);
}In fact when you access a array element using a number index, it is coerced into a string.
But with your use case, you should consider using an object:
let foo = {'foo' : ['a' , 'b','c']};
foo['customKey'] = 'd';
//Note using a for-in not for-of to iterate over enumerable & string properties
for (i in foo){
console.log(foo[i]);
}
//Using object destructing
const d = {'anotherKey': 'e'};
const newFoo = {...foo, ...d};
console.log(newFoo);