javascript - 根据项目索引附加序号后缀 ('-st' , '-nd' , '-rd' , '-th' )

Question

比如，我有一个选项值数组，例如:

var arr = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"];

我需要将其转换为格式化字符串数组，例如:

var result = ['1-st option is "a"', '2-nd option is "b", '3-rd option is "c"', '4-th option is "d"',...];

我设法实现了其中的大部分:

var result = [];
for(var i = 0; i < arr.length; i++){
    result.push((i+1)+' option is "'+arr[i]+'"');
}

它生成字符串，比如 1 option is "a"，等等。但我似乎无法处理这些后缀('-st'、'-nd'、'-rd'、'-th')。大佬们能帮我解决一下这个问题吗？谢谢!

Answer 1

您可以将必要的后缀放入数组中并选择与您的索引相对应的一个:

const arr = [...'abcdefghijklmnopqrstuvwxyz'];
const suffixes = ['th', 'st', 'nd', 'rd'];

const result = arr.map((item, i) => 
  (idx = ~~(i % 10) + 1 > 3 || ~~(i / 10) == 1 ? 0 : ~~(i % 10) + 1, 
  `${i+1}-${suffixes[idx]} options is '${item}'`));

console.log(result);

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