how to check if an array contains a specific item

Question

The below code gives the following error on

"[i]" in "if (i == ingredients[i])"

error:

element implicitly has an 'any' type because index expression is not of type 'number'

code:

    let ingredients = ["ham","onion","tomato"];
    let sandwichhas = function(ingredients:string[]){
        for(let i of ingredients){
            if (i == ingredients[i]){
                return true;
            }
        }
    }

    if (snd("tomato") && snd("onion")){
      console.log("Sandwich has tomatos and onions")
    }else {
       console.log("Sandwich has no tomatos and onions")
    }

And in the if statement below there's an error saying:

Argument of type '"tomato"' is not assignable to parameter of type 'string[]'.

Argument of type '"onion"' is not assignable to parameter of type 'string[]'.

What is the workaround for this?

Possible duplicate of [How do I check if an array includes an object in JavaScript?](https://stackoverflow.com/questions/237104/how-do-i-check-if-an-array-includes-an-object-in-javascript) — Heretic Monkey, Jun 05 '18 at 19:45
The argument to the function should either be `ingredients:string` (for a single ingredient) or `...ingredients:string[]` (for multiple ingredients) if you want to call it as shown in your question. — Heretic Monkey, Jun 05 '18 at 19:58

Vega · Accepted Answer · 2018-06-06T10:57:10.660

1

I suggest you modify your code to the following:

let ingredients = ["ham", "onion", "tomato"];
let snd = function (item) {
    for (let i = 0; i <= ingredients.length; i++) {

        if (item === ingredients[i]) {
            return true;
        }
    }
}

if (snd("tomato") && snd("onion")) {
    console.log("Sandwich has tomatos and onions")
} else {
    console.log("Sandwich has no tomatos and onions")
}

The function argument was set to ingredient, instead of a string parameter that you pass, such as "tomato" and "onion". They are of type "string", it is ingredient[], an array fro now. i in the iteration was used mistakenly also.

edited Jun 06 '18 at 10:57

answered Jun 05 '18 at 19:38

Vega

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Would it not be easier to use `ingredients.some(....)` to do the filtering? – Ric Jun 06 '18 at 13:00
Yes, but the OP is looking to fix his code as it is. array methods are in the next chapter, I think – Vega Jun 06 '18 at 17:42
Fair enough! All is well – Ric Jun 06 '18 at 17:47

how to check if an array contains a specific item

1 Answers1