Test for array of string type in TypeScript

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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 (I prefer Array.isArray(value)).

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[]!');
   }
}

In case you need to check for an array of a class (not a basic type)

if(items && (items.length > 0) && (items[0] instanceof MyClassName))

If you are not sure that all items are same type

items.every(it => it instanceof MyClassName)

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