Test for array of string type in TypeScript

Question

How can I test if a variable is an array of string in TypeScript? Something like this:

function f(): string {
    var a: string[] = [\"A\", \"B\", \"C\"];

         


        

Answer 1

You cannot test for string[] in the general case but you can test for Array quite easily the same as in JavaScript https://stackoverflow.com/a/767492/390330

If you specifically want for string array you can do something like:

if (Array.isArray(value)) {
   var somethingIsNotString = false;
   value.forEach(function(item){
      if(typeof item !== 'string'){
         somethingIsNotString = true;
      }
   })
   if(!somethingIsNotString && value.length > 0){
      console.log('string[]!');
   }
}