check null code example

Example 1: javascript check if null

if (variable === null) { //Executes only if variable is null but not undefined
  //Code here
}

if (variable == null) { //Executes if variable is null OR undefined
  //Code here
}

Example 2: js check null

if (Var === null) { 
//code goes here
}

Example 3: Null check

function exists (value) {
  return x != null ? Promise.resolve(value) : Promise.reject(`Invalid value: ${value}`)
}