15 lines
336 B
TypeScript
15 lines
336 B
TypeScript
type Header = string | number | string[] | undefined
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export default function concatHeader(prev: Header, val: Header) {
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if (!val) return prev
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if (!prev) return val
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if (Array.isArray(prev)) return prev.concat(String(val))
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prev = String(prev)
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if (Array.isArray(val)) return [prev].concat(val)
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return [prev, String(val)]
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}
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