how to convert a string array to number array?

Question

I am trying to convert a string array to a number array A quick google search have lead me to this solution.

    let numbersAsStringArray = originalQueryParams[property] ?? []
    let numbers = numbersAsStringArray.map((i) => Number(i));

where I keep getting this i

Property 'map' does not exist on type 'string | string[]'.

numbersAsStringArray is just an simple array with a number in as a string.

It seems the type of originalQueryParams[property] is not an array or at least typescript is not sure about it. You need to cast if you are sure it is an array or use a type guard. — Eldar
– Eldar, Commented May 19, 2022 at 9:52

853174 · Accepted Answer · 2022-05-19 09:52:19Z

3

It's a compilation error, not runtime error. Just tell TS that numberAsStringArray is of type string[] and it should be ok.

let numbersAsStringArray = (originalQueryParams[property] || []) as string[];
let numbers = numbersAsStringArray.map((i) => Number(i));

answered May 19, 2022 at 9:52

853174

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Comments

Jinadee Yasiruka · Accepted Answer · 2022-05-19 10:14:24Z

0

You can try let numbers = Array.from(numbersAsStringArray,Number)

answered May 19, 2022 at 10:14

Jinadee Yasiruka

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