Type error with union types even after explicit check with if statement. (Recursive type definition)

[upper igloo]

Code snippet to reproduce :

type Queries = Array<{
    value: string | Queries;
}>;

function processQuery(query: Queries) {
    console.log(query);
}

const temp: Queries = [{ value: [] }, { value: 'abc' }];

for (let i = 0; i < temp.length; i++)
    if (Array.isArray(temp[i].value)) {
        processQuery(temp[i].value);
    }

Here in the line processQuery(temp[i].value) I am getting the error Argument of type 'string | Queries' is not assignable to parameter of type 'Queries'.

One thing I can do is to remove the error is to write processQuery(temp[i].value as Queries). This seems a bit hacky. Is there a better way to handle this?

Thanks.

[whole mango]

yeah don't go for the assertion

im not quite sure why the narrowing is lost, perhaps due to the indexed access

but in general, unless you need to use i, using a for..of loop tends to be cleaner and also lets ts do a lot more work

[craggy wolf]

that_guy977#0

Playground Link

Preview:```ts
type Queries = Array<{
value: string | Queries
}>

function processQuery(query: Queries) {
console.log(query)
}

const temp: Queries = [{value: []}, {value: "abc"}]

for (const query of temp)
if (Array.isArray(query.value)) {
processQuery(query.valu
...```

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