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/** * Create a function that calls and cache a function once * @template Return * @param {() => Return} fn Function to be invoked once * @returns {() => Return} Function that returns result of first-time execution of `fn` * * @example *   import once from 'https://ksxgithub.github.io/deno-once/index.js' *   const ran = once(Math.random) *   console.log(ran() === ran()) // => true */export function once<Return> (fn: () => Return): () => Return {  let main = () => {    const value = fn()    main = () => value    return value  }  return () => main()}
export default once