使用substring（）函数提取小时和分钟。 然后使用setHours（）函数将它们分配给任意日期对象。

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const today = new Date();

const timeString = "03:37";

// Use the substring() function to extract hours and minutes
const hours = timeString.substring(0,2);
const minutes = timeString.substring(3,5);

// Use the setHours() function to assign hours and minutes
// to the "today" date object
const modifiedDate = new Date(today.setHours(hours, minutes));

console.log(modifiedDate);