javascript - 如何正确地将数组推送到另一个数组？

Question

当我运行以下命令时:

var months = new Set(["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]);
var string = "27 - 28 August 663 CE";
var words = string.split(" ");
for (var i = 0; i < words.length - 1; i++) {
    words[i] += " ";
}
var array = words;
array = $.map(array, function(value){
  return value.replace(/ /g, '');
});
const dates = {
    days : [], 
    months : [],
    years : [],
    suffixes : []
}
for (const word of words) {
    if (months.has(word)) {
        dates.months.push(word);
    } else if (+word < 32) {
        dates.days.push(+word);
    } else if (+word < 2200) {
        dates.years.push(+word);
    } else if (/\w+/.test(word)) {
        dates.suffixes.push(word);
    }
}

console.log(array);
console.log(dates);

输出不正确:

Object {days: Array(2), months: Array(0), years: Array(1), suffixes: Array(2)}

如果我运行:

var months = new Set(["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]);
var words = ["27","-","28","August","663","CE"];
const dates = {
    days : [], 
    months : [],
    years : [],
    suffixes : []
}
for (const word of words) {
    if (months.has(word)) {
        dates.months.push(word);
    } else if (+word < 32) {
        dates.days.push(+word);
    } else if (+word < 2200) {
        dates.years.push(+word);
    } else if (/\w+/.test(word)) {
        dates.suffixes.push(word);
    }
}

console.log(dates);

输出是正确的:

Object {days: Array(2), months: Array(1), years: Array(1), suffixes: Array(1)}

jsFiddle

Answer 1

因为您在第一段代码中添加了一个完全没有必要的空格:

words[i] += " ";

原因

"january "

在数组(或集合)中找不到，因为它只包含:

"january"