如何在 javascript 中从本月过滤本周

Question

I have two functions one finds this week's files and the other one finds this month's files. I want to extract/filter this week's files from this month's files.

filterThisWeek(files) {
      const firstDayOfWeek = new Date(new Date().setDate(new Date().getDate() - new Date().getDay()));
      return this.filterToday(files).filter((f) => {
        return f.date >= firstDayOfWeek;
      });
    },
filterThisMonth(files) {
      const today = new Date();
      return files.filter((f) => {
        return (
          new Date(f.date).getMonth() === today.getMonth() &&
          new Date(f.date).getFullYear() === today.getFullYear()
        );
      });

using filterThisWeek function I want to extract this week's files from this month. So filterThisMonth function should find this month's files except this week's files. I want to do it in most efficient way but I dont know how to do it.

Answer 1

I'd suggest creating functions getStartOfWeek() and getStartOfMonth() to establish the required date thresholds.

We'd then use these to create the desired limits in the filter functions filterThisWeek() and filterThisMonth() .

filterThisWeek() should return any files with a date greater than or equal to the start of the week while filterThisMonth() should return any files with a date greater than or equal to the start of the month and less then the start of the week;

 function getStartOfWeek(date) { const dt = new Date(date.getFullYear(), date.getMonth(), date.getDate()); const offset = dt.getDate() - (dt.getDay() === 0? 6: dt.getDay() - 1); return new Date(dt.setDate(offset)); } function getStartOfMonth(date) { return new Date(date.getFullYear(), date.getMonth(), 1) } function filterThisWeek(files, referenceDate = new Date()) { const lowerThreshold = getStartOfWeek(referenceDate); return files.filter(file => file.date >= lowerThreshold); } function filterThisMonth(files, referenceDate = new Date()) { const lowerThreshold = getStartOfMonth(referenceDate); const upperThreshold = getStartOfWeek(referenceDate); return files.filter(file => file.date >= lowerThreshold && file.date < upperThreshold); } function formatFile(file) { return `${file.date.toLocaleDateString('sv')}`; } const testFiles = Array.from( { length: 14 }, (v, k) => { return { date: new Date(Date.now() - k*86400*1000)}; }) console.log('This weeks files:', filterThisWeek(testFiles).map(formatFile)); console.log('This months files:', filterThisMonth(testFiles).map(formatFile));

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