Concatenate values

I need to create a way to concatenate a random number with “@gmail.com
I will use this to create multiple emails
And at each loop, a new random number is generated, therefore, a new email
It would look like
{
“Command”: “type”,
“Target”: “xpath=//[@id="root"]/div[2]/div/div/div/div[2]/input",
“Value”: “156489874988774@gmail.com”,
“Targets”: [
"xpath=//
[@id="root"]/div[2]/div/div/div/div[2]/input”,
“xpath=//input[@value=‘156489874988774@gmail.com’]”,
“xpath=//input”,
“css=#root > div.fm-tabs-content > div:nth-child(1) > div > div > div:nth-child(2) > input”
]

Concatenating strings is easy with Javascript and executescript_sandbox:

executescript_sandbox | return ${a} + ${b} | c

PS: For random number generation see Random Date of Birth generator - #2 by ulrich

Adding Strings Test macro:

    {
      "Name": "add strings",
      "CreationDate": "2021-3-31",
      "Commands": [
        {
          "Command": "store",
          "Target": "12345678",
          "Value": "a"
        },
        {
          "Command": "store",
          "Target": "@gmail.com",
          "Value": "b"
        },
        {
          "Command": "executeScript_Sandbox",
          "Target": "return ${a} + ${b}",
          "Value": "c"
        },
        {
          "Command": "echo",
          "Target": "c = ${c}",
          "Value": "blue"
        }
      ]
    }

That Cool! Worked perfectly!
Thank you for your attention.
I wish you the best (: