Put hashtags in a string in javascript

December 5, 2021

my problem is quite simple, I would like to put hashtags in a text from a list of them.
I have tried every way but I can’t find the solution.
Thanks in advance.

let arr = ['aa', 'bb']

let caption = `Hello | World `;

arr.forEach(el => {
  console.log(`#${el}`)
  caption.concat(' ', `#${el}`)
});

console.log(caption) // I want : "Hello | World #aa #bb" ; But it puts me "Hello | World"

>Solution :

concat does not modify the original string. You have to assign the returned value of concat back to caption.

let arr = ['aa', 'bb']

let caption = `Hello | World `;

arr.forEach(el => {
  console.log(`#${el}`)
  caption = caption.concat(' ', `#${el}`)
});

console.log(caption) // prints : "Hello | World #aa #bb"