ts 使用 keyof typeof

2024-10-21 11:31:39

传递参数

const cats = {

  "Coding Cat": "https://media.giphy.com/media/JIX9t2j0ZTN9S/giphy.gif",

  "Compiling Cat": "https://media.giphy.com/media/mlvseq9yvZhba/giphy.gif",

  "Testing Cat": "https://media.giphy.com/media/3oriO0OEd9QIDdllqo/giphy.gif"

};

function f(a: keyof typeof cats) {

  console.log(a);

}

// f("x"); // error

f("Coding Cat"); // ok

参数断言

const translates = {...};

function checkOrigin(origin: string): origin is keyof typeof translates {

  if (translates.hasOwnProperty(origin)) return true;

  else throw "error origin: " + origin;

}

if (checkOrigin(argv.origin)) {

  translates[argv.origin]...

}

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