34 lines
897 B
TypeScript
34 lines
897 B
TypeScript
import {colors} from './styles'
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const GRADIENTS = [
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[colors.pink3, colors.purple3],
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[colors.purple3, colors.blue3],
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[colors.blue3, colors.green3],
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[colors.red3, colors.pink3],
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]
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export function getGradient(handle: string): string[] {
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const gi = cyrb53(handle) % GRADIENTS.length
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return GRADIENTS[gi]
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}
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// deterministic string->hash
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// https://stackoverflow.com/a/52171480
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function cyrb53(str: string, seed = 0): number {
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let h1 = 0xdeadbeef ^ seed,
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h2 = 0x41c6ce57 ^ seed
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for (let i = 0, ch; i < str.length; i++) {
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ch = str.charCodeAt(i)
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h1 = Math.imul(h1 ^ ch, 2654435761)
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h2 = Math.imul(h2 ^ ch, 1597334677)
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}
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h1 =
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Math.imul(h1 ^ (h1 >>> 16), 2246822507) ^
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Math.imul(h2 ^ (h2 >>> 13), 3266489909)
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h2 =
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Math.imul(h2 ^ (h2 >>> 16), 2246822507) ^
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Math.imul(h1 ^ (h1 >>> 13), 3266489909)
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return 4294967296 * (2097151 & h2) + (h1 >>> 0)
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}
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