custom key on array in typescript

Question

I have an array of numbers like

const arr:number[] = [0,12,14,18,24,36]

that I want to assign custom keys to

arr.foo = 126

However, when I do this typescript tells me Property 'foo' does not exist on type 'number[]'

How should I type my Array to make this work?

Muhammed Albarmavi · Accepted Answer · 2019-09-14 14:35:29Z

1

you can create an interface to solve this

interface MyType<T> extends Array<T> {
    foo ?:number
}

const arr:MyType<number>= [0,12,14,18,24,36];

arr.foo = 12

answered Sep 14, 2019 at 14:29

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